Original subtitles

- [Narrator] The world's greatest structures,

push the boundaries of engineering,

all fueled by a constant desire to innovate.

- Without engineering there would be no modern world.

- [Narrator] Gigantic buildings,

complex infrastructure and ingenious inventions.

- Engineering is the key that turns dreams into reality.

- [Narrator] Many of today's incredible achievements

rely on breakthrough technologies

first devised by ancient engineers.

- It's astounding how they achieve this.

- [Narrator] Early civilizations

built on an unimaginable scale,

and with incredible precision.

- They raised a bar for engineering

in a way that no one thought possible.

- These are some of the finest engineers in history.

- [Narrator] Redefining the known laws of physics,

and dreaming up the impossible.

They constructed engineering wonders from colossal stadiums,

to mighty waterways and complex machines,

all with the simplest of tools.

- You cannot imagine the skills

people would have needed to build like this.

- [Narrator] By unearthing the mysteries left

by these ancient engineers,

we can now decode their secrets.

- That so many of their creations still survive

is testament to their engineering prowess.

- [Narrator] And, ultimately, reveal how their genius

laid the foundations for everything we build today.

(dramatic music)

Home, a place that fulfills our most basic needs.

- Since humans have formed in groups,

we've needed to have a safe place.

- It's where we belong.

- [Narrator] An immediate need for sanctuary

has propelled the human race to create

evermore extraordinary homes.

- What a house is and what it looks like and how it's built

it has changed enormously over time.

- And throughout all of this,

engineering has played a key role.

- [Narrator] Today, the construction industry

is worth 10 trillion dollars annually,

and employs 7% of the world's workforce.

And the house has transformed from a place of refuge

to a space filled with every cutting edge convenience.

- Today, we have houses that really are so sophisticated,

so advanced.

- We've gone from a cave to the most beautiful,

and extraordinary and intelligent buildings ever created.

- [Narrator] But the comfort and safety of the modern home

has only been possible through the grit, determination,

and engineering ingenuity of our ancestors

in the ancient world.

(dramatic music)

Life was harsh for our earliest ancestors.

Constantly on the hunt for their next meal,

they lived a transitory existence,

so finding a permanent place to live wasn't a necessity.

- You start off by living in what nature provides,

in the overhang of a rock, or in a cave,

or under a comfortable tree.

- There was no such thing as a permanent dwelling.

They were constantly on the move.

- [Narrator] Around 100,000 years ago,

many of our Neanderthal ancestors

would've moved from cave to cave in search of shelter,

or refuge from predators.

The earliest shelters built by humans

were structures with a frame of wood or bone,

and a covering of animal hide,

but then around 12,000 years ago came an advance

that would change not just our ancestor's homes,

but the entire way of life for humankind.

The dawn of agriculture.

- Agriculture meant humans were able to stay put,

and produce what they needed in terms of food,

to be able to survive in a single place.

- That's the point at which, certainly, there's a sea change

in the way we think about our houses.

(dramatic music)

- [Narrator] The planet's new farmers

remained in one location all year round,

and they needed a dwelling that provided security,

and shelter no matter what the season,

and 7,000 years ago across swaths of the globe

from North America to Northern Europe,

they began to create enormous

multifunctional wooden structures called longhouses.

- The longhouse is a very effective way

of really entertaining both your family,

and your extended family.

These are palatial structures, okay?

These are things that are being commissioned by elites,

so the longhouse becomes in many ways

an articulation of your power.

- [Narrator] The largest freestanding structures

of the Neolithic Era,

longhouses could be up to 165 feet long.

And building them took not only skill, but ingenuity.

It's probable that large wooden poles

were driven into the ground at depths of around three feet,

and held in place by a slotted wooden timber

called a sill beam,

before being packed tightly with soil.

Horizontal planks fastened the parallel walls together,

creating a strong frame with a load-bearing capacity

to support a large roof of thatch or grass.

- Longhouses give us a scale that we haven't seen before.

Some of them are absolutely enormous,

ceremonial, almost certainly, and communal as well.

- [Narrator] Built to house up to 30 people,

it wasn't just their enormous size and solid structure

that set longhouses apart.

Their walls were made using a new building technique.

Instead of utilizing animal hides as early shelters had,

they were constructed with the wonder material

of the Neolithic Age, wattle and daub.

- Wattle and daub is very, very simple.

You take cut hazel wood or willow wands,

and you weave those to create in essence a sort of mesh

against which you then press a daub,

which is comprised of clay, dung, and straw.

- [Narrator] Replacing the animal hide covering of the tent

with a thick clay wall of wattle and daub

represented a step change in the comfort of the house.

- It has fantastic powers of insulation.

It's as simple as that.

And as a consequence of that,

that we see it being used in structures all over the world.

- [Narrator] The Neolithic longhouse

was adapted by later civilizations,

including Native Americans and Vikings,

and remnants of those buildings,

like this site of a ninth century Viking longhouse,

are testament to the longevity of the design.

- They evolved there from the Neolithic,

all the way through into the sort of

seventh, eighth, ninth centuries,

certainly across Northern Europe.

The longhouse worked for centuries, centuries and centuries.

- [Narrator] It is a classic example of how our ancestors

used what was at hand to make a more permanent home,

but even when basics like mud and wood weren't available,

humans have used engineering ingenuity to construct a refuge

from the most unlikely building materials.

The Arctic.

A vast mass of ice and snow centered around the North Pole.

Temperatures here can plummet

to below minus 65 degrees Fahrenheit.

It's hard to imagine a more unforgiving environment.

And yet this frozen landscape

is home to one of the world's most ancient,

and most resourceful house builders.

The Inuit.

- Inuits have lived in the Arctic region

for about the last 5,000 years.

And they developed this ingenious structure

without any stone available, or even mud to make bricks,

or trees to make beams from.

- [Narrator] All that surrounds them is ice and snow.

And from it, the Inuit created one of

the most iconic shelters ever developed.

The igloo.

Built as temporary shelters for hunters,

as they crossed immense icy wastelands in search of food,

the Inuit have made igloos for centuries,

possibly millennia,

using nothing but the frozen material surrounding them.

- The classic way to build an igloo

is to have three lower courses in ice blocks.

That gives you a very solid foundation.

Then you have lighter compacted snow,

and you build that in a spiral form, so there's no weakness.

It's only, in fact,

one course that winds its way around right to the top.

- [Narrator] The true genius of the igloo's design

is the way the Inuit engineered it to be both stable,

and self-supporting.

The secret of its success, its shape.

- The shape of the igloo is based on a catenary arch,

which is the most stable arch in nature.

- If you imagine holding a chain at two ends,

and let it fall freely,

it will produce this perfect catenary shape.

And if you invert that and flip it up,

then you get a catenary arch.

- [Narrator] The catenary arch is extraordinarily stable,

and strong because the vertical force of gravity on the top

is distributed evenly through the center line

of the walls below.

Therefore, each course in the structure

holds the weight of the wall above it.

- It's one of those amazingly sort of

beautiful natural solutions.

You get this art shape

that can completely withstand its own weight,

and creating that catenary shape for an igloo

means that it's very resistant at wind pushing against it,

snow pushing against it.

These elements actually end up compressing it slightly,

and, therefore, making it even stronger.

(soft music)

- [Narrator] The Inuit perfected the igloo over centuries,

but they didn't just build

with structural stability in mind.

They also achieved the seemingly impossible,

creating a warm shelter from icy snow.

- Snow is about 95% air.

And that means that it is insulative.

So if you can create an enclosed environment

with blocks of hardpacked snow,

then the temperature inside can be very different,

much warmer than what it is outside.

- [Narrator] The extraordinary heat retention

inside the igloo is all down to its clever,

and distinctive design.

Built to exploit the fact that warm air rises,

and colder air falls the interior is terraced.

The warmest spot is the top level,

kept heated by the air rising from a fire

on the middle terrace.

As the warm air reaches the upper part of the igloo

it cools down falling to the bottom

where it sits on the lowest level which acts as a sump.

In this way, temperatures inside

can be over 100 degrees Fahrenheit higher than outside.

- And once people are inside whether from their body heat,

or lighting a fire,

the inside of the igloo can melt slightly,

and as it refreezes

it creates a thin shell of ice on the inside

that makes it stronger still.

- [Narrator] The Inuit took advantage

of the characteristics of snow

to create an unlikely place of warmth and safety

in one of the most hostile environments on Earth.

- The igloo really is a mini engineering marvel.

It is so ingenious in its simplicity.

- It's a classic example of human ingenuity

in going to a hostile environment,

and seemingly having nothing familiar with which to build,

and yet triumphing by working with the environment

rather than against it.

- [Narrator] The product of the Inuit's

inspired engineering, the igloo allowed them to hunt,

and, therefore, survive all year round.

It's such a monumental accomplishment

that it took cutting edge modern engineering

to achieve a similar feat at the other end of the world.

(dramatic music)

Antarctica, the planet's Southern polar region,

the coldest, driest, most wind-swept place on Earth.

Temperatures here can be 50 degrees Fahrenheit lower

than in the Arctic.

- Antarctica is one of the most

unforgiving places on the planet.

You've got 100 mile an hour winds,

and the sun does not come up 105 days of the year.

We're talking harsh conditions.

- [Narrator] But for over 50 years,

scientists from the British Antarctic Survey

have been conducting vital research here

into how our planet works,

and the impact of climate change on the polar ice cap.

Their current research station, Halley VI,

is located on an ice shelf that is over 400 feet thick.

It's arguably the most perilous place on Earth to build.

- It's a floating piece of ice,

which is heading towards the sea and that can crack,

so at any moment the ground could open up

swallowing the research center and everyone inside it.

- [Narrator] How can engineers create a structure

that can survive in this precarious landscape?

The answer lies in Halley's adaptable design.

- Halley VI is made from modular pods.

So it can break up into these smaller pieces.

- Then that means that if there is a sign of danger,

it can be moved quickly.

- [Narrator] After almost five years of successful operation

Halley VI faced the ultimate challenge,

when a crack in the ice came too close for comfort.

- The research center was at risk.

They had to act fast and move it

to avoid it being lost entirely.

- [Narrator] A widening crack in the ice shelf

meant that Halley VI, and its residents,

were in danger of being swallowed up by sea ice,

but the weight of each pod

could create additional destabilizing fissures in the ice.

So to ensure a safe and speedy getaway,

engineers had equipped each pod

with hydraulic legs mounted on large skis.

- You need to be able to lift the research station

out of the snow to be able to move it.

And with these hydraulic legs,

you can lift the whole research station up,

and out of that danger zone.

- What the skis do is allow the station to be dragged along.

And remember this is a big building,

so the skis beneath it help to spread the load on the ice,

which could crack at any time.

- [Narrator] Using tractors to tow them across the ice,

it took 13 weeks to move the eight pods 14 miles to safety,

a feat only made possible

by the station's groundbreaking design.

- The fate of Halley I to V was that essentially

those research stations were sacrificed to the elements,

and Halley VI with all its ingenious features

is still going strong today.

- That means that the scientists

can continue their important research

in one of the most hostile environments on this Earth.

- [Narrator] Population projections predict that by 2050,

there could be as many as 2.5 billion extra people

living in urban areas worldwide,

turbocharging the demand for housing across the globe.

The cornerstone of this building boom.

The humble brick.

1.5 trillion of them are produced every year.

That's almost 200 bricks

for every man, woman, and child on the planet,

but the basic building block of 21st century urbanization

at its genesis in the ancient world.

(dramatic music)

The Jordan Valley, a sunbaked landscape

that follows the course of the Jordan River

from the Sea of Galilee to the Dead Sea.

Here, some of the oldest known bricks

believed to date back to 7000 BC

were found near the city of Jericho.

They were made from mud that was dried

in the searing heat of the sun.

- When people came up with engineering solutions,

in this case to build houses,

they'll use the materials which is at hand.

So more often than not, if you're in the hot Middle East,

you'll use mud because it was available,

and you just shape the bricks out of the mud.

Later you'd use a mold,

and it will be left in the sun to harden.

- [Narrator] Entire cities like fifth century Yazd

in Central Iran were constructed from mud bricks,

but they were a weak building material

because even after drying they retained moisture.

- How do you make the brick made of mud or clay harder?

You fire it in an intense heat.

- [Narrator] By heating them in a kiln

to between 300 and 1,200 degrees Fahrenheit,

bricks lose all their moisture.

When temperatures exceed 1,600 degrees Fahrenheit,

chemical compounds melt to form tiny quantities of glass,

which bind the molecules of clay tightly together

in a process known as vitrification.

- What happens is in essence when it's cooled

that has in effect turned that brick into a form of stone.

- [Narrator] The Chinese first developed kiln fired bricks

around 3000 BC,

but it was one of the greatest civilizations

of ancient Europe that produced them on an industrial scale.

The Romans.

- Bricks are made literally by the million

in brickyards outside Rome and other major Roman cities.

They take a technology that had been around

for thousands of years, the brick,

and really put rockets under it.

- [Narrator] The ability to mass produce the brick

changed the home for good,

but as its empire expanded,

Roman builders faced an enormous challenge.

A rapidly growing population needed new houses,

and they needed them fast.

At its peak around 100 AD

the Roman Empire stretched from Britain in Northwest Europe

to Egypt in Northeast Africa

covering an area of 2.3 million square miles.

And it's likely that the population of the city

at its heart, Rome, topped one million.

- These are all people who've got daily jobs

who play an intrinsic part of the working of Rome itself.

So they've got to live somewhere.

- [Narrator] The challenge was to accommodate them

in affordable housing within a relatively small space.

Building out wasn't an option, so they built up.

- Why do you build upwards?

It's because land is expensive.

So you stack more floors above your bit of city land,

and people start to live in multi-story

vertical apartment blocks.

- [Narrator] Known as insulae,

the blocks were usually built over five or six stories,

and consisted of six or seven apartments,

housing up to 40 people.

- There'll be some shop fronts.

There would be apartments over the shop fronts,

not quite like downtown Manhattan, but not far off of that.

- [Narrator] Insulae were constructed at breakneck speed.

Thanks to the ready availability of mass produced bricks,

and one other vital ingredient.

Concrete.

- The Romans weren't the first people to use concrete,

other people used it before the Romans,

but they refined the technique.

It was a real turning point in the way that the Romans

built their houses.

- [Narrator] Concrete is an easy-to-use,

yet durable building material.

The Romans began to work with it from around 300 BC,

and extraordinarily some of it still survives today.

- The key thing which made Roman concrete better

than anything that had gone before was that it contained

a new ingredient, volcanic ash.

- [Narrator] Concrete is made of water,

sand, gravel, and cement,

which binds the other materials and hardens over time.

Adding volcanic ash, or tephra,

and solidified lava in place of cement,

made Roman concrete remarkably durable.

As lava from a volcano cools,

glass and crystals form within it.

These crystals react with hydrated lime in the tephra

to form calcium-aluminum-silicate-hydrate,

which acts as a binder that glues the concrete together,

making it stronger and more resilient.

- What you've got is something that sets as hard as stone.

- [Narrator] Versatile and relatively easy to produce

without concrete the Roman insulae

would never have been built so quickly.

- It streamlined the house building in the Roman world.

Instead of having to extract stone remotely,

you could actually make the concrete on site.

So it was there and it was quicker and faster to use.

- It's like the Henry Ford of building materials, right?

You can turn it almost into a production line.

It's a strong, durable, cheap, brilliant substance.

- [Narrator] Mass produced bricks and concrete

allowed the Romans to build houses at an astonishing rate,

but four protective walls

would be nothing without the shelter of a roof.

And just like bricks and concrete,

the kiln fired tiles topping the homes of the Roman Empire

were developed from concepts

borrowed from other civilizations.

- The ancient Chinese were the first

to kiln fire roof tiles, and that's from around 3000 BC.

And if you jump ahead in time,

and you move to the Mediterranean world by say 500 BC,

you find that the ancient Greeks

had a really interesting system

of interlocking tiles for their roofs.

- [Narrator] The system was known as imbrex and tegula.

The tegulae, flat tiles with raised sides

were placed in horizontal rows.

The adjoining edges were then covered

by semicircular imbres tiles and mortared into place.

- The advantage of using the imbrex half pipe curved tile

means that the water is gonna run easily off the roof.

- The rain bounces off the semicircular tiles,

flows down into the troughs,

and taken on down towards the gutter.

So they developed this quite clever interlocking system

that means there's no holes, or gaps, or cracks

that rain can get into.

- [Narrator] Roman house builders

took the Greeks roofing system,

and just as they did with bricks and concrete,

they supersized it.

- They mass produced the tegula and imbrex tiles

on a scale that we would recognize as industrial today.

- [Narrator] The Romans perfected the concepts

of older civilizations to mass produce bricks, concrete,

and imbrex and tegula roof tiles,

revolutionizing house building forever.

- It's allowed them to build houses on a huge scale,

making them accessible

for far more people across the empire.

- What they achieved was truly extraordinary.

And that house building technology was absolutely central

to the success of that empire.

- [Narrator] From the moment our ancestors

first sought shelter in caves,

humans have needed to feel safe and secure

in the place they call home.

- In the past houses have been protected by animals,

guard dogs, by higher walls, and also by moats.

- [Narrator] Today, there's one device we all rely on

to keep the doors, gates, and windows of our houses secure.

The lock.

But the key to the high tech security devices

that protect our homes is to be found millennia ago.

(dramatic music)

Ancient Egypt.

A highly sophisticated civilization

that lasted three millennia,

and gifted the world the most iconic monument of antiquity,

the Pyramids of Giza.

Still standing over 4,000 years after construction,

they are an enduring symbol

of the Egyptians engineering brilliance,

but the accomplishments of that era

weren't limited to monumental structures.

The Egyptians also took great strides forward

in mathematics, medicine, art, and literature,

and they even found time to perfect the lock.

- The earliest lock dates back to the Syrians,

which is what is modern-day Iraq,

but then the Egyptians took that further,

and advanced that technology in now what is known

as the Egyptian lock.

- [Narrator] Early locks were simply a bolt across a door

released from outside through a hand-sized opening.

What set the Egyptian version apart?

It was one of the first locks to use a key.

The upper part of the lock casing

had a series of movable pins.

When the bolt was moved into place,

the pins would fall down into holes in the bolt,

holding it firmly and locking the door.

To unlock an angled key was inserted in a slot in the bolt.

The key had pins,

which exactly matched those in the lock casing,

so that when the key was tilted upwards it lifted the pins,

releasing the bolt and unlocking the door.

- What it did require was some very skilled,

and precise use of tools

to be able to get those pins to align perfectly,

and, therefore, unlock.

- [Narrator] In the Egypt of antiquity,

wooden pin tumbler devices were widely used

to protect palaces and sites of religious importance.

And they are still in use today in Egypt,

Zanzibar and India,

but back in ancient times,

it was the Romans who unlocked the true potential

of the Egyptian's idea,

manufacturing locks from metal

with more complex mechanisms and keys.

- It's common to find these keys at Roman dig sites.

And they look very similar to what we would use today.

- [Narrator] But our modern locking systems

don't just look like they're ancient predecessors.

They also operate in a remarkably similar way.

- The old cylindrical pin tumbler system

that the Egyptians invented was the basis

of Linus Yale's lock, which he patented in the 1860s,

which is the one that many of us use today

to get through our own front doors.

- [Narrator] Today, electronically controlled smart locks

released by cell phones, fingerprints,

or even face recognition deliver personalized security,

literally, to our front doors.

All of this is achieved without a physical key,

making it the most seismic shift in home security

since the ancient Egyptians invented the pin tumbler lock,

3,000 years ago.

The concept of what makes a house a home

has developed over the millennia.

From basic caves and rudimentary shelters

through to solid constructions of first wood,

and then bricks and concrete,

the human race has grown to expect

increasing levels of comfort,

and amenity from the buildings we call home.

Today, our houses are as varied

as the people who live in them,

but large or small, contemporary or traditional,

they all utilize one incredible material.

Glass.

- Glass made homes what they are today.

To be able to see out and allow the light in

that really transformed our home spaces.

- [Narrator] Glass is an amorphous solid

with an unusual molecular structure.

It doesn't have the rigid crystalline makeup of a solid,

but molecules aren't as loosely arranged

as they are in liquids.

And because of this quirk in its makeup,

it's an extraordinary building material.

- Glass is a wonderful substance.

At high temperatures it's incredibly versatile and liquid,

and you can pull it and you can stretch it,

and make it into any shape that you want.

Then as it cools it is strong enough,

rigid enough to hold its shape.

- [Narrator] Made by melting the silica in sand

at very high temperatures,

glass is a mainstay of modern-day house building,

but it's origins lie way back in centuries past.

Ancient Egypt was one of the first civilizations

to produce manmade glass,

thanks to its ready supply of raw ingredients.

- What you basically need is sand,

and then you need soda, or something to act as a flux

to lower the melting point of sand.

Egypt and Mesopotamia

is where those materials were available,

and that's when it first appears.

- [Narrator] Early glassmaking was small-scale

producing nothing more than beads,

but when the Romans conquered Europe and North Africa,

they had the skill and vision to grasp

the true potential of glass as a raw material,

using it to create vases, jars, and bowls.

They even stretched lumps of molten glass to make windows

bringing something new to the home.

Light.

- Roman houses generally had quite small windows,

but once they got confident in making glazed windows,

they could light up interior spaces.

- [Narrator] These early windows cast new light

on what a home could be,

but it was difficult to see clearly through thick panes

handcrafted from lumps of glass.

By the fourth century AD,

the Romans realized that using blown glass

made much clearer windows.

- Blown glass had been around for a very long time.

They'd been blowing glass for 300 years by then.

So it wasn't a sort of technological leap.

It was the putting together of the ideas.

- [Narrator] To make window panes,

the blown glass was shaped into a cylinder.

The top was sliced off and a crack made in the side.

The result was a curved form of glass,

which was then briefly reintroduced to the furnace

where the heat softened it allowing it to flatten

to form a thinner, clearer pane of glass.

- When you looked out of the window

in the early Roman period you'd just see shapes.

You wouldn't be able to see any details.

If you were looking through one of the cylinder blown panes,

you'd be able to see much more detail.

- [Narrator] At the dawn of their empire,

no one had window panes,

but thanks to the efficiency of Roman infrastructure,

and mass production,

glass windows became a common feature of their houses.

- Townhouses had windows.

Great luxurious villas they had windows as well.

So people were really adopting this technology.

- [Narrator] The Romans did create

colored glass vases and jars,

but their windows were made from almost colorless panes.

It wasn't until 700 years after the fall of Rome,

that the potential of stained glass windows

was fully realized.

Medieval churches and monasteries across Europe

were bathed in light from their colorful panes.

And it's possible that builders inspired by their beauty

began introducing glass windows to homes,

but the enormous plate glass common today

was only made possible by a feat of engineering brilliance

in the 20th century.

Today, it's possible to manufacture enormous window panes

of up to 55 feet.

- Glass can do all sorts of things now,

so it really is an artistic and an architectural tool

that can be used in all sorts of ways

to very dramatic effect.

- [Narrator] The incredible versatility of glass

in the modern home wouldn't have been possible

if it wasn't for one manufacturing breakthrough.

The float glass process.

Developed by British Engineer,

Alastair Pilkington in the 1950s,

it uses extremely high temperatures

to create incredibly flat glass.

- The glass has to be heated

to about 3,000 degrees Fahrenheit in order to do this.

And it allows huge sheets of glass to be made.

So it was an absolute technological breakthrough.

- [Narrator] The hot liquid glass

is poured continuously from a furnace

onto a shallow bath of molten tin.

Stable in liquid form at very high temperatures,

it provides an even surface,

and the glass floats on it like oil floats on water

to form flat panes.

After controlled cooling, known as annealing,

the glass emerges as a polished product

with virtually parallel surfaces.

- This process can allow us to control

the thickness of the glass down to 100th of an inch.

- [Narrator] Using the float glass method,

a plant can produce

over three and a half thousand miles of glass every year.

And adding chemicals to the molten mixture,

or allowing it to cool more quickly

can produce glass of different colors and strengths

making it an endlessly versatile building material.

- Glass brings so much to our homes today in terms of light,

and warmth and comfort.

And yet this was started off by that Roman idea

of bringing glass windows into the home.

(upbeat music)

- [Narrator] One of the hallmarks of the modern house

is the high-level of sanitation

provided within its four walls.

Living in a home without running water,

and flushable toilets in the developed world

is almost unthinkable in the 21st century,

but the seeds of this engineering triumph

that we take for granted

were sewn by one of the great civilizations of antiquity.

(dramatic music)

Crete.

One of the largest islands in the Mediterranean,

and home to one of Europe's most ancient civilizations,

the mighty Minoans.

- Minoan society was incredibly civilized.

And what it does is it controls all of the sailing routes

around the Mediterranean,

and as a consequence of that becomes an incredibly wealthy,

and sophisticated civilization.

- The Minoans were renowned for their engineering.

Their crowning achievement is the royal palace at Knossos.

Built around 1700 BC,

it's regarded as Europe's first ever city.

- It's quite extraordinary

that they actually managed to design,

and then build this in the Bronze Age.

- [Narrator] In summer, Crete has almost no rainfall,

but three and a half thousand years ago,

the genius of Minoan engineering

made it a comfortable place to live.

- Water management is absolutely crucial.

And the ancient Minoans

were one of the earliest civilizations

to come up with a working solution.

- [Narrator] Precious rainwater from roofs,

and the overflows from above ground cisterns

was carried down through buried drains of pottery pipe

into underground storage tanks.

- Their water management systems

were examples of exceptional engineering so skilled

with designing and building these

that some are still in use today.

- [Narrator] This expertise meant Minoans

had water supply to their houses throughout the year,

even in the bone dry summer months,

but they were also the first known civilization

to engineer another home convenience.

- I think for us in the modern world,

what we're really looking for

in terms of water management system

is the ability to flush away certain unwanted substances.

And I think it's fair to say that the Minoans

did come up with the first form of flushing toilet.

- [Narrator] The Minoan toilet consisted of a wooden seat,

and earthenware pan.

Water was poured through a hole in the floor

immediately outside the toilet door,

while an under floor channel

linked the hole with the vertical clay pipe under the seat,

and into a system of sewage pipes outside the property.

The forerunner of the toilet as we know it today,

the water closet was invented in England in the 1590s,

but incredibly the Bronze Age version

was improving the homes,

and lives of Minoans 3,000 years earlier.

- This really is hydrology coming up face-to-face

with civil engineering,

and producing a system of water management

that is incredibly sophisticated.

- [Narrator] A need to keep warm

was one of the primary impulses

that drove our earliest ancestors

to build shelters and houses,

and on the journey from cave fire

to the automated modern heating we enjoy today,

there have been many monumental breakthroughs.

One around 200 BC delivered new levels of home comfort

to well-off Romans.

- The Romans liked their creature comforts,

and they enjoyed heated buildings in the winter.

- So they actually create an incredible

central heating system.

- [Narrator] The Romans ingenious innovation

was an early form of underfloor heating,

known as a hypocaust.

The heat source was a wood-burning furnace

positioned just outside the house.

Heat from it was directed through pipes

into a cavity underneath the floor,

which was held up by stacks of bricks know as pilae.

Hollow tiles called box flue tiles built into the walls

created a flue which drew heat upwards

to warm the higher floors of the house.

- The hypocaust is clever engineering

because instead of just huddling around a campfire

warming your hands,

the heat of that fire is transported,

and distributed throughout the building.

- [Narrator] A major technical achievement,

the hypocaust is an important engineering milestone

in the development of the house,

heralding a new era of comfort for well-off Romans.

- It marks another step of sophistication and innovation.

It allows you to have all the benefits of heating

without actually the mess and noise and smoke,

and sort of a fire in your living space.

- So it's making the house

a much more pleasant environment to live in.

- [Narrator] The hypocaust

is such a brilliantly designed piece of engineering

that after the fall of the Roman Empire,

there was no comparable central heating system

anywhere in Western Europe until the 20th century,

but vast areas of the ancient world

didn't have to battle with biting cold, but scorching heat.

Iran.

With evidence of human settlement

dating back over 100,000 years,

it's probably one of the oldest inhabited regions

in the world.

- The civilizations that lived in Persia, modern-day Iran,

have been hugely influential in the history of mankind.

- Incredible developments in innovations,

in terms of engineering,

but also art and culture

really were inherited by the modern state of Iran.

- [Narrator] Summers in this ancient arid land are long,

and temperatures regularly sore above

100 degrees Fahrenheit.

- The country of Iran has a massive central desert plateau,

and that makes it incredibly hot.

And the people who live there really needed to find a way

that they could live in this very difficult environment.

- [Narrator] Thousands of years ago, Persian house builders

were among the first to hit on an ingenious way

of keeping homes cool in the desert heat.

The wind catcher.

- Wind catchers are tall, striking chimney-like structures

that can be seen protruding from old houses

throughout modern-day Iran.

- In these hot, dry flat areas, you will get winds,

you will get breezes.

And what you're doing with a wind catcher

is catching that wind,

channeling it down into your building,

so that you're cooling your inside spaces.

- [Narrator] The earliest wind catchers

dating back millennia come from both Egypt,

and ancient Persia.

At its simplest,

open vents facing towards the prevailing wind

draw cool air down the chimney of the wind catcher.

Once inside this air passes over an indoor pool cooling it.

This cooler air then displaces the warmer air in the house,

sending it back up the tower of the wind catcher,

and exhausting it outside the building.

- Moving air and water are both coolants,

so that transformed the sense of living within a box

of still dead hot air into something much more

like sitting next to a stream with a fan.

- [Narrator] Centuries old wind catchers

have been shown to reduce indoor temperatures

by almost 20 degrees Fahrenheit.

- I just think it's an amazing piece of technology.

The Iranian wind catcher

is the original air conditioning unit.

- [Narrator] Wind catchers are so effective

that they even helped keep the Persian ab anbar,

domed underground drinking water reservoirs almost ice cold

as outside temperatures

rocketed above 100 degrees Fahrenheit.

- Wind catchers are genius because they're passive.

They require no energy.

There's no moving mechanics there at all.

It's simply harnessing nature to human advantage.

- [Narrator] Today in hot arid areas of the world,

cooling systems account for 60%

of total building energy consumption,

but wind catchers with advanced technologies

designed to meet the needs of the 21st century

could help cut energy use,

while leaving little or no carbon footprint.

Could effective engineering solutions like this

be the future of housing?

Some of the most alarming climate change modeling

predicts that by the end of this century,

the world will be nine degrees Fahrenheit hotter

than it was in pre-industrial times.

And as our planet gets warmer,

cities are set to really feel the rise in temperature.

That's because buildings and roads absorb,

and re-emit the sun's heat

more than the natural environment,

creating a phenomenon known as the urban heat island effect.

- The urban heat island effect

can make metropolitan areas up to 22 Fahrenheit hotter

than more green spaces.

- [Narrator] Research predicts

that the influence of the urban heat island effect

will only get stronger as the global population grows.

So how do we cool our cities without energy hungry air con?

One solution is to go green, literally.

This is One Central Park Sydney.

At over 350 feet the larger of its two tower blocks

is covered in over 35,000 plants

making it the world's tallest vertical garden.

- What the plants do is they absorb the heat

rather than having that heat bounce off from concrete

onto a pavement and be trapped in the city.

- The plants on the outside of the building

also act as insulation.

It cools the apartment in summer,

and keeps it warm in winter.

- [Narrator] The vegetation even helps reduce

the temperature in the environment around the building.

Hundreds of tower blocks like this could have the potential

to combat the urban heat island effect

by helping to cool down entire cities,

but its vertical garden isn't the only

innovative eco-friendly element of these apartments.

- The most striking feature of this building

is a huge platform jutting out from the top tower.

- It's almost like an upside down dance floor

in between the two buildings.

- [Narrator] The platform which juts out almost 140 feet

from the 28th floor of the taller tower block

is part of a heliostat system

designed to redirect light to shaded areas of the complex.

- Light from the sun is bounced from mirrors on the roof

of the smaller tower up to 320 reflective panels,

which then directs that light down onto the ground

in the space between the two towers.

- [Narrator] It's stunning vertical garden,

and groundbreaking heliostat system

make Central Park Sydney a world first.

- This is high-rise living

with solutions to cut down the carbon footprint.

It's the future of the house.

- [Narrator] By the middle of the 21st century,

the world's population is said to reach 9.8 billion.

- This will throw up enormous challenges

for the engineers of today to create our homes for tomorrow.

- How do we build cheaply and efficiently,

and environmentally responsibly

to accommodate that number of people?

- [Narrator] And the challenges in engineering

our future homes don't stop there.

- We now live in a world

which is colored by extremes of weather.

- We see floods in Europe.

We see hurricanes sweeping across the United States.

We have to rethink our houses.

- [Narrator] As we step into the future,

what we build and how we build it will be transformed.

- There are substantial challenges.

We have to build things which are protected against flood,

and fire and heat.

- So we need to build smarter,

and use more innovative materials and processes.

- And it's engineering that will help us to redefine

how we accommodate ourselves,

how we learn to live and adapt in this changing world.

- [Narrator] As the engineers of today

face the challenges of the future,

they are fired by the innovative ideas,

and the incredible vision of their predecessors

in the ancient world.

(dramatic music)