Original subtitles

Narrator: Ancient artifacts discovered on the shores

Narrator: Ancient artifacts discovered on the shores of a Swiss lake, reveal evidence of a lost warrior tribe.

of a Swiss lake, reveal evidence of a lost warrior tribe.

Dr. Cantor: He saw some timbers sticking out of the water.

And something about that must have piqued his curiosity.

Within the hour, he had recovered

40 objects from the bay.

Dr. Leonard: There are 14 swords and 8 spearheads.

All of them were well-preserved in the cold riverbed.

But who made them? And how did they end up

in such abundance at this specific location?

Narrator: Mysterious coffins are found in a cave

high on the Tibetan Plateau.

Anthea Nardi: Inside each cave is a set of chambers

arranged in stories, like an apartment complex.

And right there in the corner of one of the chambers

are three wooden coffins.

Dr. Riskin: So what are these coffins doing

all the way up here in a cave in the Himalayas,

and who put them there?

Narrator: A grisly discovery is made

on the Norwegian archipelago of Svalbard.

James Ellis: While looking for a group of 17 missing sailors

at a house in an abandoned Swedish colony,

the hunting group are shocked to find five lifeless bodies,

frozen under a tarp.

Dr. Leonard: There are no signs of violence or foul play,

but there's a horrific feeling that something awful happened.

But what could have killed them?

♪ [show theme music]

Narrator: These are the strangest mysteries,

trapped in the coldest places.

Lost relics.

♪♪

Forgotten treasures.

♪♪

Dark secrets.

♪♪

Locked in their icy tombs for ages.

♪♪

But now, as ice melts around the world,

♪♪

their stories will finally be exposed.

♪♪

♪♪

Narrator: Located 80 miles north of the Swiss Alps,

the frigid waters of Switzerland's Lake Neuchatel

stretch for 23 miles,

making it the country's largest lake

entirely within its borders.

Dr. Cantor: The area around Lake Neuchatel

is mostly gentle and pastoral,

lots of rolling hills and valleys covered in wildflowers.

It's like a scene from a picture postcard.

But that's in the summer.

The winters can get extremely cold.

The coldest day on record was in 1956,

when the temperatures dropped to -4 degrees Fahrenheit.

Dr. Leonard: The northeastern tip of Neuchatel

is a bay area called La Tene,

which today plays host to a small resort town.

It's one of the many popular and picturesque destinations

of the so-called Three Lakes District

of Lake Biel, Lake Neuchatel, and Lake Murten.

Anthea Nardi: Historically, the Three Lakes region

has been an important passageway

for trade and transportation between the Rhine,

the Danube and the Rhone valleys.

So the relatively small area has a long history of inhabitants

throughout the ages.

Narrator: In November of 1857,

a Swiss fisherman by the name of Hans Kopp

stumbled upon an odd sight in the Bay of La Tene.

Dr. Cantor: Kopp was on his way to explore another site,

at a settlement called Concise, also on Lake Neuchatel.

But at La Tene, he saw some timbers

sticking out of the water.

And something about that must have peaked his curiosity

because he went over to investigate.

Within the hour, he had recovered

40 objects from the bay.

Dr. Leonard: Among all these artifacts,

there are 14 swords and eight spearheads.

All of them were well-preserved in the cold riverbed.

Based on the wear and tear, it looks like

they've been here for a long time.

But who made them, and how did they end up in such abundance

at this specific location?

Narrator: Kopp's discovery was just one of many

Lake Fever explorations in the region,

that was first triggered by an 1854 find in Lake Zurich.

Dr. Cantor: In the winter of that year,

the unusually low water level enabled the discovery

of a Neolithic dwelling at Meilen, Switzerland,

called a "pile dwelling."

Pile dwellings are parallel rows of houses along the shore,

built on raised wooden floors,

so the dwellings appear to be supported by sticks or stilts.

Leonard: The Zurich discovery caused a bit of a frenzy,

helped in no small way by the European press.

So the entire Three Lakes region suddenly became the focal point

for archeologists looking for evidence of Stone Age villages.

Anthea Nardi: Sure enough, the area contained

over 50 pile dwellings, from the Neolithic

to the end of the Bronze Age.

Most of these were found underwater or in bogs,

which provided ideal conditions for the preservation

of organic materials, like wood and textiles.

James Ellis: But there was a fundamental problem with

the theory that La Tene was just another Stone Age dwelling.

All the items retrieved were made of iron.

None of it was bronze.

So did that mean La Tene was once home to

a community of people from the Iron Age?

And if so, what happened to them?

Narrator: During the Iron Age period,

between 1200 BC and 600 BC,

several tribes from an ancient warrior culture,

known as the Celts, migrated across Europe.

Dr. Cantor: The tribes and groups were Indo-European

in origin, and geographically,

they ranged from Britain and Spain,

all the way to Transylvania in the East.

The Celts that populated most of modern day Switzerland

and France belonged to a tribe called the Gauls.

Dr. Leonard: The society of the Gauls was full of warriors.

And today they're best known for their reputation as fighters.

But their daily life and community revolved

mostly around farming and trade.

Anthea Nardi: Ancient Celtic civilization has left

very few traces.

We know that their buildings were made mostly of mud,

straw and manure, and they didn't stand the test of time.

But when it came to iron work, they were master craftsman.

James Ellis: The iron objects retrieved from Le Tene,

bore many of the hallmarks of Celtic ironwork,

like intricate decorations on swords and scabbard,

and images of aquatic animals and horned horses.

Sure, they were weapons, but they were also

stunning works of art.

Narrator: The La Tene site became the central focus

for many established archeologists.

Curious to learn more about the mysterious fate of the Celts

and convinced there was more to discover, they were right.

Dr. Cantor: As a result of a water diversion project

known as the "First Jura Water Correction,"

the water level of Lake Neuchatel was lowered

by almost nine feet.

Not only was the entire bay area

at La Tene accessible by foot,

it also exposed hundreds more artifacts for them to collect.

James Ellis: They found hundreds of iron weapons,

much like the ones Kopp had retrieved,

spears, shields and swords,

some of which were still in their scabbards.

But they also discovered a wide range of domestic items

from Celtic civilization,

broaches, hooks to fasten belts,

axes and tools.

Bridle bits for a horse carriage

and even a spoked wooden wheel

from the carriage itself.

Narrator: In the late 1800s, excavators uncovered

the remains of two ancient bridges at La Tene,

spanning the original location of the River Thielle.

Dr. Cantor: The bridges, Pont Desor and Pont Vouga,

were about 250 feet long, in a parallel formation,

spaced about 300 feet apart.

Their discovery supported the idea that the area was a hub

for trade and transport, going back thousands of years.

Dr. Leonard: But the two bridges might also explain

why La Tene had such a concentration of artifacts

in a relatively small area.

Is it possible all these weapons, jewelry and tools

were not local after all?

Did they land in the bay by accident while in transit

from some other locations?

Or was La Tene some kind of border crossing?

Narrator: As the archeologists continued looking

for more personal clues about the Celts,

they discovered something very personal

and kind of gruesome under the bridge sites.

James Ellis: Tens of thousands of bones

and several skulls were retrieved.

Analysis of the skeletons revealed no obvious

health problems, disabilities or observable deformities.

However, many of the skulls showed visible signs of trauma,

and it wouldn't be the last time Celtic skulls and bones

were discovered under the remains of a bridge.

Narrator: In the winter of 1965,

archeologists uncovered the Cornaux-Les Sauges bridge,

less than two miles downstream from the La Tene site.

Based on the buckling of the support posts,

they determined that the bridge had collapsed,

and collapsed quickly,

as indicated by the sediment layers.

Dr. Leonard: In addition to more iron weapons and artifacts,

there were nine complete skeletons

and individual skulls and bones,

found wedged in between the beams of the rubble.

The bridge likely collapsed from natural disaster,

probably a violent flood.

And the people on the bridge at the time, got swept under,

along with their belongings.

So is it possible the citizens of the La Tene site

met the same fate?

Did some kind of sudden disaster or structural collapse

lead to their untimely death?

Narrator: A closer examination of human remains at Le Tene,

led archeologists to another equally grim conclusion.

Anthea Nardi: Many skulls showed clear blows or cuts

to the head, at the front and middle cranial vault.

The wounds are clean, sharp and in a straight line.

The slash pattern in one skull indicated that the victim

didn't move or even resist

at the time the wound was inflicted,

which could possibly mean he was unconscious.

But the more likely story is, he was already dead.

James Ellis: Another skull had a series of severe cuts

and slash marks at the base.

Plus, evidence of blunt-force trauma.

These actions were all carried out from behind,

and clearly intended to separate the skull from the torso.

In other words, these warriors were dismembered after death.

Narrator: The archeologists weighed their findings

with what they already knew about ancient Celtic warfare.

Dr. Cantor: Most accounts of Celtic warriors,

paint them not only as being fierce,

but as being particularly brutal to their foes.

There are many reports in Greek and Roman sources,

that Celtic warriors engaged in particularly violent rituals,

such as human sacrifice, and the mutilation of enemies'

fresh corpses immediately after death.

Dr. Leonard: Similar evidence was discovered

at the excavation site of another Celtic ruin

at Ribemont-sur-Ancre in France.

At this location, the decapitated remains

of hundreds of young men were found arranged around posts.

Many of these bodies showed wounds

that were the cause of death,

but many other injuries were inflicted postmortem.

Anthea Nardi: The site in France is largely interpreted

as a grotesque trophy display.

According to this theory, the Celtic victors propped up

the slaughtered and decapitated remains of their enemies

on a wooden gallery or palisade.

Anthea Nardi: The reasons for doing so

are still up for debate.

Some suggest it was done as a warning

to other potential enemies.

A sort of, 'this could happen to you.'

Others see it as more ritualistic.

The Celtic warriors were known to be highly superstitious,

so this could be interpreted as a sacrifice

or as an offering to the Gods.

Narrator: Experts consider the possibility

that La Tene was used as a trophy site

by the tribe of Celtic warriors,

to exhibit the remains of a defeated army.

James Ellis: Those strange looking timbers

poking out of the water,

first seen by Hans Kopp in 1857,

could have been the remnants of the platform or gallery

used for sacrifices and religious ceremonies.

Dr. Cantor: The timbers, the human remains,

the large cache of iron weapons,

it all supports the idea that La Tene was the site

of a vicious Celtic battle

around 225 BCE.

But there's still so much we don't know.

Who exactly were the two tribes,

and what were they fighting for?

Dr. Leonard: Unfortunately, most of what we know about that era

comes to us second hand from Roman sources,

including Julius Caesar himself.

Caesar was one of those who described the Celtic Gauls

as ritualistic and superstitious.

He also called them timid.

But the Romans were at war with the Gauls,

so he might have been just a little biased.

Narrator: The Bay of La Tene and Lake Neuchatel

continues to fascinate us with its secret histories,

human stories, and clues

to help us understand who we are today.

♪♪

Narrator: In a remote region of northern Nepal,

the Mustang District stretches across the Himalayan mountains

and into the Tibetan Plateau.

The area is known for its natural beauty

and harsh conditions.

Dr. Riskin: The mountains are covered in snow year round,

and the winter temperatures can drop as low as

-4 to -13 Fahrenheit.

So, stunning to look at, but that high altitude

and that cold, dry climate make this place inhospitable.

Dr. Cantor: Mustang was once an independent Tibetan Kingdom

with its own monarchy, but it was claimed and annexed

by Nepal in 1795.

In the 20th century, the region became a focal point

for oppression by the Chinese, due to its ties to Tibet.

In 1962, all foreigners were forbidden to enter,

and this ban wasn't lifted until 1992.

So much of its culture and traditions

were hidden for 30 years.

Dr. Agbedor: The opening of the region allowed tourists

and other outsiders to visit and experience

the remote mountain ranges and plateaus.

It also opened the door for historians and anthropologists

to learn about its mysterious past.

Narrator: At an altitude of 10 to 12,000 feet

in an area called "Mebrak",

a team of German archeologists is exploring

a group of ancient dwellings,

cut right into the rock face,

when they come upon something entirely unexpected.

Anthea Nardi: Inside each cave is a set of chambers

arranged in stories like, like an apartment complex.

And right there in the corner of one of the chambers

are three wooden coffins.

Dr. Riskin: Each coffin is small. It's like 3 or 4 feet.

They almost look like tiny beds.

The wooden boards are covered with geometric ornaments.

These things are painted with animal figures.

And two of the coffins have these strange, small,

rectangular doors on the front.

So what are these coffins doing all the way up here

in a cave in the Himalayas,

and who put them there?

Narrator: The archeologists carefully remove

the coffin lids and reveal something shocking.

Dr. Cantor: Inside, are the mummified remains

of multiple human bodies.

They're lying under woven bamboo mats,

which appear to function as some kind of shroud.

And as with the coffins,

the bodies are exceptionally well preserved.

Dr. Agbedor: Lying next to the remains,

there are various grave goods

that range from personal items

like bronze bangles, glass beads and necklaces

to items of clothing.

There are also objects from daily life,

such as pottery vessels, wooden containers and woven baskets.

Dr. Riskin: The remains of several domesticated animals

were also found surrounding the coffin beds.

This included the mummified heads of 11 goats and two sheep,

and the body of an adult horse,

which had to be dismembered to fit inside the cave.

This abundance of ritual offerings is not uncommon,

if you look at ancient cultures around the world.

But nothing like this had ever been found

in the Himalayan Mountains before.

So who were these people?

Narrator: The greater area of Central Asia

has a rich history of archeologists uncovering

mummified remains across the region.

Dr. Cantor: In 2010, a team of Chinese researchers discovered

roughly 200 mummified human remains in the Tarim Basin,

which is in China's northwest autonomous region of Xinjiang.

It's a mostly inhospitable desert area north of Tibet,

surrounded by a stark circle of mountains.

Dr. Agbedor: The bodies of the dead were still wearing

the clothes that they were buried in,

with felt caps,

large woolen capes

and leather boots.

When geneticists analyzed the DNA,

the results revealed the people

were of mixed ancestry:

East Asian, South Asian,

and even Indo-European.

Dr. Riskin: The Tarim Basin site contained several grave goods,

just like the ones at Mebrak Cave, including woven baskets,

carved masks and bundles of an herb called ephedra;

that may have been used in rituals or as a medicine.

So you've got very similar funeral rituals.

Which begs the question, are these maybe two outposts

of the same culture, at the same time?

Narrator: 28 samples of wood from the Mebrak location

are sent for radiocarbon dating

at three separate laboratories and compared to existing

dendrochronological samples in a database.

Dr. Cantor: The cave was used roughly 2,000 years ago

for a period of over 400 years.

Specifically from around 400 BCE to 50 C.E.

Samples from the mass grave in the Tarim Basin,

revealed that the mummies and artifacts there

dated back almost 4,000 years.

So there's likely no connection to the mummies in China,

since they're separated by about 2,000 years.

Dr. Agbedor: The anthropometric data indicated

the Mebrak mummies were ethnically related to Mongolians

and likely came to the Mustang region from Central Asia.

The cultural artifacts, as well as the burial ritual itself,

further showed that there were definite links to Central Asia.

Narrator: The archeologists return to the Mebrak caves,

to take a closer look at the placement and arrangement

of the bones and skulls.

Dr. Cantor: Most of the bones were no longer

in the proper anatomical arrangement,

and given the high concentration of bodies,

that made it difficult to determine

whether a particular skeletal element,

belonged to one individual or another.

Dr. Agbedor: But in the western section of the chamber,

several bodies were dismembered and without heads,

while their skulls were deposited in another corner.

Many of the bodies that were intact,

were laying in a crouched position,

with their wrists tied and bound together,

and their hands placed under their chins.

Is it possible, that they were victims of torture or murder?

Human sacrifice was practiced at one point or another

all over the world, including

regions with a Mongolian influence.

Narrator: In 2018, archeologists discover the skeletal remains

of 14 adults and children,

in North China's Inner Mongolia autonomous region.

Anthea Nardi: The remains were discovered buried

at the bottom of a round pit, almost 10 feet deep.

The pit was beneath the ruins of an ancient building complex,

northwest of the Imperial Palace of Shangjing,

which was the first capital of the Liao Dynasty.

Dr. Cantor: There were chop and cut marks on some of the bones,

inflicted while the victim was still alive.

Clear evidence of a violent death.

Likely human sacrifice.

They also discovered a second rectangular pit,

filled with the skeletons of three horses,

bones of camel hooves and skulls of cattle and dogs.

It's believed that these people and animals,

had been offered as sacrifices

for the construction project of the ancient building complex.

Dr. Riskin: But while the discovery in the Himalayan cave

does have a few similarities,

including the presence of domesticated animals,

there's no direct evidence to suggest

that those human bodies were intended

as sacrificial offerings.

Narrator: Hoping to discover other possible explanations,

researchers make a detailed examination

of the bone material.

Anthea Nardi: The Paleo pathological analysis did reveal

evidence of interpersonal violence on a few skulls.

Specifically, deep fractures running across the forehead,

which were inflicted by a sharp object.

But there is nothing to indicate the victims had been beheaded,

or violently decapitated while still alive.

Dr. Agbedor: As for the wrist binding,

the bodies were likely positioned that way postmortem,

possibly to aid in the transport

of the corpses long distances

and up into the mountain caves.

But why go to all that trouble?

Dr. Riskin: We could be looking at a practice called

the Tibetan Sky Burial.

Many people in this part of the world

adhere to Vajrayana Buddhism, which embraces the idea of

the transmigration of spirits.

And in that way of thinking,

there's no need to preserve the body,

because it just becomes an empty vessel after death.

Anthea Nardi: The sky burial was a ritual in which

a human corpse was placed on a mountainside,

to be exposed to the elements and scavenged by birds.

Once the flesh was disposed of,

the remaining bones were then placed in a mortuary,

along with valued artifacts and personal possessions.

The high altitude would certainly suggest

a connection to Buddhist sky burials,

but so far, there's no direct proof.

Narrator: The mortuary evidence in the region offers

tantalizing clues about the early populations

who migrated into the high Himalayas.

And further exploration of similar sites

within the Upper Mustang region

could provide an enriched view of this complex landscape.

♪♪

Narrator: Midway between the northern coast of Norway

and the North Pole, lies the Nordic island chain of Svalbard.

The largest island, Spitsbergen, is a mountainous land

covered in glaciers, dramatic fjords

and stunning natural beauty.

Dr. Leonard: With an area just over 15,000 square miles,

Spitsbergen is slightly larger than all of Switzerland,

and with a population just under 2,900 people,

most of the inhabitants live along the western coastline

in Longyearbyen, the largest settlement

in all of the islands.

With such a small, concentrated population in one area,

most of Spitsbergen is barren and unpopulated.

Anthea Nardi: With long cold winters and short cool summers,

Spitzbergen's climate is Arctic,

and it experiences Polar night

from late October to mid-February,

when the island is plunged into complete darkness,

with the sun never rising above the horizon.

James Ellis: The plant life in Spitsbergen is limited,

due to the harsh climate and limited soil nutrients,

preventing trees from growing.

Yet, several resilient species still thrive,

like mosses, lichens, grasses

and some flowering plants.

Dr. Riskin: The island can look really different,

from one region to the next.

The vegetation in the fjord areas in the central west coast

can be surprisingly rich with plants and colors.

But if you go to the far northeast,

it's barren, desert-like tundra.

Narrator: Spitsbergen is a harsh and unforgiving environment,

filled with stories of men and women going missing,

never to be seen again.

On one such occasion,

a group on a hunting expedition

make a grisly discovery.

James Ellis: While looking for a group of 17 missing sailors

at a house in an abandoned Swedish colony

called Kapp Thordsen,

the hunting group are shocked to find five lifeless bodies,

frozen under a tarp.

As they search the grounds,

they try to enter the house,

but the door is locked from the inside.

Anthea Nardi: Forcing the door open,

it's eerily quiet and the air is stale.

As they search the home, they find

six more dead bodies in various bedrooms,

and then four more in shared living quarters.

That's a total of 15 lifeless bodies,

found in this secluded home, with two people missing.

Dr. Leonard: There are no signs of violence or foul play,

but there's a horrific feeling that something awful happened.

It's very clear that the men here had experienced

severe illness before their deaths.

But what could have killed them?

Narrator: As the hunters searched the house for clues,

they find a diary that fills in some of the important details.

Dr. Riskin: Let's back up. The men, now dead or missing,

were originally part of a large group of sealing vessels,

traveling from Tromsø, Norway,

when this massive storm sealed the bay with ice,

trapping the ships and the 59 sailors on board.

They had no way to escape the island of Spitsbergen,

they had limited supplies,

so they really had no choice but to overwinter

in the frozen wilderness.

Nardi: The crew approached a Swedish explorer for help,

but he didn't have enough supplies,

and he suggested sending some of the men to stay

at a Swedish house in Kapp Thordsen,

that had been set up by a mining company

but eventually abandoned.

The house was furnished and filled with enough canned food,

beer, supplies and ammunition to last the winter.

James Ellis: 17 men without families were selected

and rode over 200 miles in the frigid cold Arctic weather,

to get to the house in Kapp Thordsen.

That would be the equivalent to the distance

between New York City and Washington, D.C.

Not a simple journey in the slightest.

Dr. Leonard: When the men got to the house,

they were finally at ease, feeling safe and sound

in this well built structure that would protect them,

and be their home for the winter.

They spent the days hunting polar bears and reindeer,

until the nights got too cold,

and they'd have to rely on the stored food.

Narrator: At this point in the diary,

things take a turn for the worse.

Nardi: Not even two months in, two of the men became quite ill,

and by the end of December, everyone was quite sick.

In the journal they recorded all of the food eaten,

the weather conditions and the sickness.

But they can't understand why everybody is sick.

Dr. Riskin: Two of the men die in mid-January

after what's described as a hard sickness.

In February, two more die, and then, one by one,

every one of the men succumbs to the illness.

Dying in a home they thought would be safe

for the Arctic winter months.

But the mystery still remains,

what killed these 15 men

and where are the missing two?

Narrator: Reading the diary over and over again,

and looking for clues, the hunting party concludes

that it must have been some sort of disease

that took out these men.

James Ellis: Tuberculosis, also known as consumption,

was a widespread disease during this period.

It is caused by bacteria called Mycobacterium tuberculosis,

which spreads through the air

when an infected person coughs or sneezes.

This releases tiny droplets containing the bacteria

into the air, which can be inhaled by others,

allowing the germs to enter the lungs and cause infection.

Tuberculosis still kills over a million people a year,

and is one of the most common causes of death globally.

Dr. Leonard: While not typically fast acting,

tuberculosis can affect entire families over time.

In the pre-antibiotic era, TB spread slowly within households,

and multiple family members could become infected

and die over a period of months.

The disease was particularly devastating in poor,

crowded living conditions.

Dr. Riskin: One of the most infamous stories of tuberculosis

is that of the Bronte family, which included

Charlotte, who wrote Jane Eyre

and Emily, who wrote Withering Heights.

That family lived this secluded and remote life,

and tuberculosis ripped through their household,

killing five of the family members,

including the two sisters,

who both died before they turned 40.

Anthea Nardi: It's likely that the Bronte sisters

contracted tuberculosis from each other,

or from the same environmental sources,

given that they lived together in one house.

And just like the men in the house at Kapp Thordsen,

they didn't all die right away.

It took months or years for the virus to spread.

Narrator: Looking through the diary again,

the hunters begin to suspect that the men

may have suffered from a common condition

that plagued sailors and fishermen during this time.

Dr. Riskin: A significant condition that plagued sailors

during this time, was something called scurvy.

Scurvy is a nutritional deficiency of vitamin C.

Vitamin C is essential for making collagen.

That's a protein that's in your skin,

it's in your blood vessels, it's in your bones.

You need it for repairing tissues.

And if you don't have collagen because of a lack of vitamin C,

you end up with a disease called scurvy.

James Ellis: Symptoms of scurvy include fatigue and weakness,

swollen or bleeding gums,

loss of teeth, joint and muscle pain,

anemia, fever and even death.

It is thought that more than 2 million sailors

died of scurvy between the 16th and 18th centuries alone.

Dr. Leonard: Sailors were specifically affected by scurvy,

due to limited access to fresh fruits and vegetables

during their long sea voyages or extended periods of isolation.

And it was especially common in the age of exploration,

when the ships carried mostly nonperishable foods

that lacked vitamin C.

Narrator: The sailors at Kapp Thordsen were warned of scurvy,

and given specific instructions on how to avoid it,

by eating scurvy grass and drinking lime juice.

These practices were first put into place

by Captain James Cook.

Anthea Nardi: Cook actively worked to prevent scurvy

for his crews, making him a pioneer in maritime health.

Cook made sure the crew's quarters were clean

and had good ventilation,

and all of the sailors had a proper diet,

including sauerkraut, which has traces of vitamin C,

specific herbs, lime juice and fresh fruit,

whenever they could get it.

Narrator: Thinking the men must have been too lazy or foolish

to heed the warnings about scurvy,

the hunting party declares it as the cause of the deaths

and buries the bodies in a common grave.

But new information comes to light when a team of researchers

decides to take another look at Kapp Thordsen.

James Ellis: Something about the story just didn't make sense

to the team of researchers.

Why would the sailors ignore the scurvy warnings?

All of the sailors seem to have gotten sick

at roughly the same time,

which would have been peculiar if scurvy had been the cause.

Narrator: As they walk the grounds of the house,

they notice a large assemblage of lead food cans,

that must have been left there by the sailors.

Dr. Leonard: Lead poisoning is something they hadn't

considered, but the story of Admiral Sir John Franklin's

expedition might have some startling similarities.

In 1845, Admiral Franklin led an Arctic expedition

to chart and navigate the Northwest Passage.

This was a sea route through the Arctic, that many hoped

would provide a quicker way to sail between Europe and Asia.

However, his expedition ended in disaster,

with all 129 men aboard his ships perishing in the Arctic.

Dr. Riskin: That whole expedition was a giant tragedy,

that involved getting stuck in the ice, abandoning the ships,

setting out on foot, dragging supplies on lifeboats and sleds,

and eventually...cannibalism.

Anthea Nardi: Years later, when a team from Alberta University

exhumed and studied three sailors in permafrost

from the expedition, they were surprised to find

high concentrations of lead in the hair samples.

Bones that were found close by, also showed

high concentrations of lead,

which must have been from the tin food containers

that the sailors ate from.

This brought them to the conclusion that

lead poisoning was possibly the biggest cause of death

for the expedition.

Narrator: Realizing this could well be the cause of death

for the men at Kapp Thordsen,

the researchers dig up the grounds

and find the other two bodies that were missing,

giving them a total of 17 dead men.

James Ellis: As they examine the remains,

the hypothesis becomes a reality.

These men have extremely high levels of lead in their system,

and must have been suffering from acute

and sub-acute lead poisoning.

Narrator: After years of being labelled as lazy or dumb,

for not fighting off scurvy,

the men who died at Kapp Thordsen,

can finally get some respect,

as sailors who contracted lead poisoning through

tin-can rations, that were supposed to help

keep them alive, but instead, ended up killing them.

♪♪

Narrator: 793 million miles from Earth sits Saturn,

the sixth planet from the sun and one of the largest planets

in our solar system.

James Ellis: Unlike Earth, Saturn is not solid.

Instead, it's a giant gas planet made up mostly of hydrogen.

146 moons of all different shapes and sizes surround it.

Dr. Leonard: The sixth largest moon, Enceladus,

features a relatively smooth, bright white surface

that reflects nearly all of the light that strikes it,

making it one of the brightest objects in our solar system.

This high reflectivity results in

extremely cold surface temperatures,

approximately -330 degrees Fahrenheit.

Dr. Riskin: Dust and debris from meteorites

tends to be really dark.

The fact that Enceladus is so bright,

reflecting almost all the light that hits it suggests,

first of all, that it's a relatively young moon.

And second of all, that whatever is all over its surface

comes from the moon itself, not from other places.

Narrator: As scientists and astronomers explore

our solar system using the Cassini probe,

a mission that would ultimately orbit Saturn 294 times

and teach us almost everything we know about the planet,

a photograph of Enceladus is transmitted back to Earth,

that leaves the people at NASA stunned.

Dr. Riskin: The images show this strange, whitish glow

coming from the south pole of the moon.

It's like something's shooting out of Enceladus,

and feeding into Saturn's rings.

James Ellis: The various plumes come in different sizes,

both large and small, from many locations around the moon's

famed 'tiger stripes' fractures.

Appearing white or blue,

the plumes can scatter sunlight,

creating a bright, glowing effect,

particularly against the dark backdrop of space.

Dr. Leonard: Whatever the substance is,

it's streaming miles above Enceladus,

and must be ejected by a huge amount of energy.

This isn't the type of activity you're expecting

out of a cold, dead moon.

So what's causing these plumes?

Narrator: Mysterious plumes of unidentified substance

remind scientists of another moon not so far away.

James Ellis: One of Jupiter's moons, Io,

is just slightly larger than Earth's moon,

and is riddled with hundreds of volcanoes.

The surface looks very colorful,

with yellow, red and black patches.

There are several active volcanoes that erupt,

sending plumes from Io into space.

Dr. Riskin: One of the larger plumes is named Prometheus,

after the Greek god who brought fire to humanity.

The Prometheus plume is blue in color.

It rises 46 miles above the moon's surface,

and this thing has been visible in every single image

taken of that area, since 1979,

which means this thing has been consistently active

for decades at least!

Dr. Agbedor: The plumes consist primarily of sulfur dioxide,

but they can also include other materials,

like sulfur or silicate lava,

because Io is the most volcanically active moon

in our solar system.

When the hot sulfur dioxide gas is expelled from the volcanoes,

it cools rapidly and it expands into space,

which forms a type of snow.

Narrator: As the Cassini probe does a flyby of Enceladus,

it gets a direct sample from one of the plumes

with some surprising new information.

Dr. Leonard: Cassini detected a combination of volatile gases,

including water vapor, carbon dioxide and carbon monoxide,

along with organic materials

emanating from what can now be identified as a cryo-volcano.

These are essentially ice volcanoes, that erupt

a mixture of volatile compounds instead of lava.

Narrator: Switching their research to cryo-volcanoes,

the team of scientists studying Enceladus,

look to other moons in our solar system with similar features.

Dr. Riskin: Neptune's largest moon, Triton,

has a diameter of 1,680 miles,

making it about 80% the size of Earth's moon.

But here's why Triton is really special.

Unlike all the other large moons in the solar system,

Triton has a retrograde orbit, which means,

it is going around its planet in the wrong direction!

Dr. Agbedor: As one of the coldest places

in our solar system,

Triton has temperatures as low as

-400 degrees Fahrenheit!

It receives 900 times less sunlight than Earth.

Much of that sunlight is reflected off its icy surface,

similar to Enceladus.

But despite its frigid temperatures,

Triton is an active moon with very few craters,

which suggests that it's a young surface,

that's being continuously reshaped

by geological processes.

Dr. Leonard: It's thought the plumes of Triton

are caused by sublimation, a process that occurs

when a substance transitions directly from a solid to a gas,

without passing through the liquid phase.

A common example is dry ice.

This process happens when the molecules absorb enough energy,

typically from heat, to escape their solid structure.

Dr. Agbedor: The geyser-like eruptions of Triton

are most likely caused by sunlight

vaporizing ice in the moon's shell,

forcing it to erupt with substances like nitrogen gas,

methane and possibly water.

So instead of molten rock, these plumes release icy materials.

Narrator: As more and more information comes in

from the Cassini probe,

a new clue might answer some of the questions,

as to how these plumes are created.

Dr. Riskin: Cassini offers the first clear evidence

of hydrothermal activity on Enceladus,

thanks to its cosmic dust analyzer,

which detects small rock particles rich in silicon.

Now those particles likely formed when hot water,

containing dissolved minerals from the moon's rocky interior,

traveled upwards, coming into contact with cooler water.

Narrator: Armed with this new information,

researchers turn their attention to another moon

with similar characteristics:

Jupiter's Europa.

Dr. Agbedor: Europa is believed to harbor a vast,

sub-surface ocean that may be larger

than all of Earth's oceans combined.

Because of its distance from the sun,

the moon has an average surface temperature

of around -370 degrees Fahrenheit.

James Ellis: The smooth, bright surface of Europa

is primarily composed of frozen water,

and displays features indicative of a dynamic

and active geological history.

The criss-crossed cracks and ridges that almost give it

a marbling effect might be caused by floating ice

on the subsurface ocean.

Dr. Leonard: Like Enceladus, IO and Triton,

Europa emits plumes from its surface,

that likely originate from a hidden ocean beneath the ice.

This raises the exciting possibility

that a spacecraft could analyze this

potentially life-supporting environment,

without having to land on the moon.

Dr. Riskin: Europa has a funny orbit.

The same side of that moon is always facing Jupiter,

but the orbit is elliptical,

so that means that it gets closer and farther away

from Jupiter as it goes,

and that changes the strength of the gravitational pull.

As a result, you get these tides

that stretch and relax the surface,

and all that is called tidal forces.

Those tidal forces likely cause the cracks we see

on Europa's surface, and if Europa's ocean exists,

those tidal forces could also lead to volcanic

or hydrothermal activity on the seafloor,

which would lead to plumes that shoot out into space.

Narrator: Similarly, the scientists studying Enceladus

find information that supports this theory of how gravity

might affect the plumes coming out of the small moon.

Dr. Leonard: Just like Europa, Enceladus is thought to be

affected by the gravity of the planet it orbits.

Saturn is 95 times the mass of Earth.

Combine that with the fact that Saturn has almost 150 moons,

there is a lot of gravity there.

Dr. Riskin: Because it's so far away from the Sun,

sunlight can't really warm Enceladus up effectively.

Instead, it's the gravity of Saturn,

tugging and stretching Enceladus,

creating friction that generates enough heat

to potentially melt the ice inside that moon.

James Ellis: The gravitational tugging of Enceladus

is thought to create hydrothermal vents

in its subsurface ocean.

This heat can create conditions suitable for hydrothermal

activity similar to what is observed on Earth's ocean floor.

The combination of liquid water, heat and chemical interactions

at these vents makes the subsurface ocean

a promising location in the search

for extraterrestrial life.

Dr. Agbedor: That is what really excites everyone,

and the reason why this discovery matters so much.

There is a wealth of chemical activity taking place,

which is reminiscent of the processes

that occurred on Earth billions of years ago,

ultimately leading to the emergence of life.

And so this has massive amounts of water

and a powerful source of energy,

which are two key ingredients to support life.

If life hasn't developed there already,

it could very well be on the verge of doing so.

Narrator: Enceladus' subsurface ocean is considered

one of the most promising locations in the Solar System

to search for life.

Whatever the future holds,

it's sure to capture the attention of scientists

for years to come, as they continue to unravel

the mystery of this icy moon.

♪♪