Original subtitles

- [Tony] Eerie hums, haunting drones, piercing buzzing...

[buzzing]

Strange sounds are sweeping the globe,

but who or what are behind

these disturbing noises tormenting mankind?

- What is that sound? [humming]

It's driving me [bleep] crazy.

- From the mountains to the ocean and even Mars...

Are these eerie signals a message from an alien race?

- It was a civilization that once lived there

and is now extinct?

- [Tony] What is causing a reverberating hum

in Southern California?

- [Tony] Could this be the sound of Bigfoot?

[creature growling]

- That was probably

the most unique Bigfoot encounter I've ever had.

- [Tony] On this special episode

of "The Proof Is Out There, Unexplained Edition,"

our team of top experts investigates

evidence of bizarre sounds from around the world.

[creature calling] - What is that noise, bro?

- Then we'll pass a verdict.

The Proof starts now.

[dramatic music]

Good evening and welcome to "The Proof Is Out There".

Hollywood can produce some impressive sound effects,

but what happens

when a real-life massive sound straight out

of an explosive blockbuster echoes throughout Los Angeles?

Just look and listen.

January 23rd, 2021, Los Angeles, California.

It's a chilly, rainy day when warehouse worker Eric Reyes

is startled by a strange sound coming from the sky.

He grabs his cell phone and records this.

[humming]

The typical sounds of rainfall are echoed

by a distant, other worldly hum.

The sound is constantly reverberated

throughout the whole community.

[humming]

- At first I was in denial and I was like,

I don't wanna hear this sound.

But it kept on going, so I went outside my patio.

I started filming the sound. I was scared a little bit.

That really freaked me out. I did some research.

Some people would say something hiding behind the clouds.

[humming] - And what's truly odd

is that similar sounds were reported in other parts

of Southern California around that time.

Author Jason Martel explores the theory

that sounds like these,

as well as many others heard around the world,

could be entering our atmosphere from space.

- One of the possible theories

of what we're hearing is plasma wave.

Plasma is the fourth state of matter, very similar

to gas, but all the particles are ionized.

Occasionally the sun emits coronal mass ejections,

which are large explosions of plasma

from the magnetic field of the sun's corona.

- [Tony] According to NASA, these coronal mass ejections,

or CMEs, can create currents in Earth's magnetic fields,

altering frequencies that can be heard

as a strange cacophony of noise.

[humming] And while this theory

has become increasingly popular,

others think that these sounds could be part

of a pattern specific to Southern California.

- Many have theorized

that these could also be related to the San Diego booms.

[booming]

They were recorded in March, June, and December of 2021,

the same year as the Los Angeles sounds.

[booming] - Those mysterious

San Diego booms were never

explained, and while San Diego is right next

to a naval base on nearby Coronado Island,

officials for the base denied any involvement.

However, some still speculate that it could be part

of an experimental program involving sonic weapons,

weapons like the LRAD, or Low Range Acoustic Device,

which is being used around

the world for crowd control and dispersal.

- Many have said that the Navy

has acquired armed merchant ships

and have outfitted them with modular weapons systems.

Is it possible that the sounds we're hearing are coming

from these new naval capabilities right off the coast

of Los Angeles?

- If the Navy were secretly arming merchant ships,

LA seems like a pretty good place to do it.

The Port of LA is the busiest in the Western Hemisphere

and moves nearly $300 billion worth of cargo every year.

But are some of these ships being secretly retrofitted

for the future of naval warfare?

We turn it to our experts to investigate.

- The federal government constantly monitors

coronal mass ejections and their impact across the world.

Taking a look at the Planetary K Index,

which measures overall electromagnetic waves out

in space, we see that this was not related

to a solar storm or electromagnetic waves.

- [Tony] With the outer space theory neutralized,

we turn to see if these sounds are even real

in the first place. - In this recording,

there was no indication that it had been assembled

or layered or put together from other sources.

It appears to be authentic.

The area in which the recording was made does

have some industrial operation,

so I compared the recording to some sounds

of manufacturing equipment.

[rattling]

So this manufacturing system has tonal qualities,

so frequencies that we can observe in the spectrogram.

It also has a repetitive sound,

but the overall effect is similar to what we heard

in the example recording.

[rattling]

[humming]

So it is conceivable that the sound might be

from some sort of industrial source.

- [Tony] Of course, these two sounds

are not identical, but again,

it's the tonal qualities in the spectrogram that Maher

is focusing on.

- Some of the other characteristics

are a little bit different,

and so it's hard to attribute it exactly

to a particular manufacturing process.

But it's certainly plausible that that could be

from an industrial source.

- Our verdict?

We're calling this an unidentified industrial noise.

Between this and the still unexplained San Diego booms,

you may wanna pack some earplugs the next time

you're headed to Southern California.

The Mariana Trench of the Pacific Ocean

is nearly 36,000 feet deep.

To put that in perspective,

you could pick up Mount Everest and drop it

in the trench, and the mountain would still be

a mile below the water's surface.

Due to such enormous depths,

the trench still has not been widely explored.

So when a monstrous sound was detected there,

it was a mystery for us all.

It's November 16, 2014.

Dave Mellinger and his team of marine researchers drop

a passive acoustic ocean glider into the deepest part

of the Pacific Ocean, the Mariana Trench.

There, they record this.

[humming]

The five-part sounds, which last no longer

than 3.5 seconds each,

include deep moans at frequencies as low as 30 hertz,

low rumbles, high-pitched screeching,

and a strangely metallic finale that reaches frequencies

as high as 8,000 hertz.

The noises return. Let's turn up the volume.

[humming]

A weird auditory mixture of the biological

and the mechanical, leading to confusion

over the likely cause.

- We ran across this very strange, unusual sound,

which we later called the Western Pacific Biotwang.

We started hearing it and we're like,

what the heck is that sound?

But we really didn't know what this sound was.

We just had not heard this kind of thing before.

[humming]

- [Tony] Journalist Erin McCarthy says

the Biotwang emanates from a place so remote,

it might as well be another planet.

- Up until recently,

more people had been to the moon.

So you're looking at an area of the planet

that is basically like an alien world.

I think it's fair to say that this sound

is fairly alien-like, which has led some people

to speculate that aliens have set up underwater bases

in the Mariana Trench because it's more like

their world than it is ours.

- [Tony] But that isn't the only possible explanation

for the mechanical sound.

- A potential explanation is some kind

of top secret military transmission.

- The US Navy

has conducted underwater experiments for decades.

Some of the most famous include

the Sealab underwater habitats.

There was an underwater nuclear bomb test.

And more recently, they've started testing bullets

that can shoot from underwater.

Until recently, scientists assumed that the murky depths

of the Mariana Trench were quiet.

But research teams have since discovered that it

is actually abuzz with sound.

A NOAA research oceanographer has even said that there

is almost constant noise from both natural

and man-made sources.

So the question remains,

what created these mysterious sounds?

Our experts go on a deep dive.

First, could the sound be seismic activity?

The Mariana Trench is a hot bed of earthquakes thought

to be due to the high pressure at the bottom of the trench.

- There's hundreds of thousands

of earthquakes happening each year.

It's one of the more common acoustic signals

we have in our oceans.

[humming]

This is super low frequency

hand it's this continuous rumble,

which is way different than the Biotwang.

[humming]

[humming]

We could say definitively it's not caused

by seismic activity.

- [Tony] Next, Dr. Shea Steingass focuses on the bio

in the Biotwang.

She thinks it could be an animal, but what?

- In recent years,

there have been sightings or biopsies of whales

that we thought were extinct.

And in fact, they weren't.

We're only getting small glimpses of what's going

on in places like the Mariana Trench.

- [Tony] Steingass believes the Biotwang was made

by one such species, not one believed extinct,

but one that's rarely seen.

- The researchers that study these types

of animals were able to determine that this is probably

a Bryde's whale.

They spend a lot of time at the surface,

but they're very elusive and we don't know a lot about them.

[humming]

- [Tony] But hang on, as Dr. Steingass mentioned,

the Bryde's whale spends the majority of its time

in the top 10 meters of the water column,

not the bowels of the planet's deepest ocean trench.

And there's another problem here with the persistence

of the sound.

- These whales primarily use these sounds

for mating, which happens mostly in late winter.

But this sound, they've recorded it all year round

at this location.

- Okay, so the ocean scientists say

the Bryde's whale theory is possible, but as we just saw,

it doesn't really fit all the facts.

The sound is similar enough to other whale calls

to rule out anything mechanical.

But our verdict?

This is an unidentified ocean animal,

quite possibly a species we've never seen before.

- Strange sounds terrorizing entire communities

seem to be a growing trend.

Several years ago, residents of a small suburb

in Oregon were tortured

by a still unexplained whistle they claimed

was driving them insane.

In our next story, a new sound is disturbing the peace,

only this time in the outer boroughs of the Big Apple.

Brooklyn, New York, November 2022.

Mo Hussein is walking home at night when he hears

a mysterious sound echoing through his neighborhood

of Fort Greene.

Using his camera phone, he records this.

[humming] - What is that sound?

- [Tony] And according to Mo, this noise has been going

on and on, haunting residents for over a year.

- It's driving me [bleep] crazy.

- It's the type of sound that kind of drills

into your head slowly, hour after hour,

until finally you kind of jump up from your desk

and you say, oh my God, what is that sound?

It made it difficult to sleep

and it definitely caused headaches.

- [Tony] Out of desperation, Mo and his neighbors called

the city, but the sound would mysteriously turn off any time

officials showed up to investigate.

- The timing of the occurrence of the hum led

a lot of people to believe that it was some sort

of construction equipment

that could hopefully be turned off.

- [Tony] But with no clear answers

from any city representatives,

another theory emerged based

on the hum's potential frequency.

- There's a phenomenon, the worldwide hum,

that can be heard by certain people all over the world.

It's been reported

to cause symptoms including nausea, headaches, dizziness...

- [Tony] Some people theorize that the worldwide hum

is tied to underground gas pipelines.

This map created by hum sufferer

and mechanical engineer Steve Colehouse shows

the overlapping proximity of hum reports

and pipeline locations.

But while the Brooklyn pipeline has been in the works,

it is far from finished.

So Grundhauser explores a more frightful theory,

one involving sonic weapons. - In 2016 in Havana,

Cuba, members of the U.S.

Embassy staff woke up in the middle of the night

to a loud piercing sound

that caused dizziness, vertigo, and nausea.

- [Tony] Although Cuba denied any responsibility

for this sound and its effects,

later dubbed Havana Syndrome,

a recent study claims to show brain abnormalities in all

the people who heard this noise,

leading many to believe it was a sonic weapon.

- Similar symptoms have been reported

by hundreds, some have even said thousands, of U.S. spies

and diplomats all over the world.

[humming]

- This strange hum hasn't

been Brooklyn's only audio oddity.

Several years ago, residents of Brooklyn Heights started to

hear a mysterious high-pitched chirping noise around

Cadman Plaza Park.

It turned out that was coming

from a state-of-the-art pest-repelling sound machine

sitting out on someone's balcony.

Could something so simple be what's plaguing Fort Greene?

We'll let our experts sound off.

- The Havana sound has a very high frequency,

but the recording in Brooklyn, the lower frequency of this

is nothing like the Havana tone.

- [Tony] Some experts concluded that the Havana sound,

at least that one recording of it,

was just local crickets anyway.

But that still doesn't explain what could be behind

this infuriating hum in Brooklyn.

Maher thinks he has an idea.

- It's reminiscent of what is referred

to as a Helmholtz resonance,

and this is the resonance that you hear if you blow

over the top of a pop bottle or a jug.

[bottle humming]

With this sound that is heard in Brooklyn,

the amplitude tends to vary up and down,

which to me is an indication that this might be

a resonance effect, like wind blowing through a railing

or a building that might cause

this continuous resonant quality sound.

[humming]

- [Tony] Solid structures like steel railings

or metal bars contain molecules that vibrate

at a frequency specific to their makeup.

And when hit by something like high winds,

the Helmholtz resonance can kick in.

- You may amplify existing small vibrations,

turning them into larger ones.

The Brooklyn hum can just be blamed on some sort

of wind tunnel effect towards structures

that can wiggle back and forth at just

the right frequency to create this annoying sound.

- It's driving me [bleep] crazy.

- While we agree with our experts

that the Brooklyn hum is most likely a product

of resonance created by the wind,

we still don't know exactly which structure the sound

is coming from.

Our verdict, partially unexplained sound resonance.

Meanwhile, the people of Fort Greene have started

the petition to stop the mysterious noise.

They hope making noise

of their own will yield some well-earned peace and quiet.

- If you go anywhere in the world

and ask someone what Bigfoot looks like,

you'd get similar answers most every time.

But what if you asked what Bigfoot sounds like,

this recording might be the answer.

This story goes all the way back to California in 1971.

Al Berry and his friend Ron Morehead have come

to the Sierra Nevada mountains

to investigate mysterious noises reported

by a bewildered group of hunters.

What their microphone picks up becomes the first

of a series of recordings now known as the Sierra Sounds.

[growling]

The recordings capture a series

of guttural grunts, howls,

and growls thought to be made by an alleged Bigfoot.

- The very first sounds were very aggressive.

Could be considered very scary, but again,

they weren't coming after us.

So we don't know the intent, we don't know the agenda,

we don't know what it was.

- [Tony] Ron claims that later he even interacted

with these mysterious creatures before getting his first

glimpse of one.

[shouting]

I was responding back to them and that was probably

the most unique Bigfoot encounter I've ever had.

Field researcher Cliff Barackman says the Sierra Sounds

are the gold standard of Bigfoot vocalizations.

I've spoken to several witnesses that have reported

this kind of sound that says something

about the authenticity of not only their sighting,

but these sounds.

- The recordings range from guttural growls...

[growling] To wild woofs.

[shouting] To something

that almost sounds like language.

[muttering]

- There's a retired crypto-linguist

from the U.S. Navy.

He's realized that there are phonemic patterns

that repeat in the sounds.

Those are words.

Sasquatches might be talking to one another.

- Now, here's the thing about Bigfoot sounds.

They're easy to fake and easier to misidentify.

We've heard examples of both.

So let's dial things down a bit and check

in with our experts.

- The sound is really loud,

and it's of quite a low pitch and frequency,

so it travels far.

So it's likely that it came from a large animal.

- [Tony] Next, we bring the recordings

to soundscape ecologist Dr. Ben Gottesman.

- So here we have three phrases.

- [Tony] First, Gottesman examines the guttural sound.

[growling]

Next, the whooping.

- The second has these low to high up-sweep.

[shouting]

[Gottesman shouting] - And finally, the chatter.

[muttering]

- And those almost sound like words.

- [Tony] The question, could those come

from any known large animals native to the area?

- We're now going to listen to the sound of an elk bugling.

[elk bugling]

[growling]

The sound of an elk bugling has much longer tonal signals.

This is not a match.

Now let's listen to the sounds of a black bear.

[bear growling]

[growling]

[shouting]

While the frequency range is similar,

the shape and complexity of the signals

are totally different.

The Sierra sounds are on a much more advanced level.

- [Tony] Gottesman also rules out an assortment

of smaller creatures since they lacked lung capacity

to create calls that loud and low.

Gottesman also notices that whatever made these sounds

has an enormous vocal range.

- If this is produced by a single creature,

there is just a remarkable acoustic diversity

that this alleged species has.

If they are an animal, I can't confidently point

to one, especially one that's native to North America.

- [Tony] So could the sounds have been made

by other humans?

- I do not believe it is possible

for this to be human because it has a great variance

of going to very high pitch down

to a very low growl all within seconds.

[animal growling]

We're not capable

of that without blowing out our vocal cords.

My conclusion is that they are real recordings

of Bigfoot and I base that on knowing how remote

that location was and the impossibility for another human

or other thing to have made those sounds.

- The Sierra sounds recordings are legitimate.

Scientists and even some linguists point to them

as evidence multiple Bigfoots were communicating

with each other, as well as with Morehead and Berry.

Our verdict here? Unidentified animal sounds.

Regardless of what made them,

the Bigfoot legend continues to speak to us.

The big question is, are we really listening?

With over 364 million acres, Alaska,

known as the last frontier state,

has no shortage of mysterious phenomena.

Something that the hikers

in our next story experienced firsthand.

It's April 2019 in Anchorage, Alaska.

Two hikers are climbing the scenic O'Malley Peak

when something truly bizarre happens and they start filming.

[humming]

As one of the hikers reaches into the sky,

a strange buzzing sound fills the air.

She appears to be able to manipulate the sound

by squeezing the air and placing her hand on her head.

She winces as the sound continues,

as if she can feel the disturbance

coursing through her.

- I don't like how it feels. I'm putting my hat back on.

- [Tony] Journalist Erin McCarthy says

this could be related to a mysterious phenomenon

that some believe has long plagued the region.

- Some have speculated that perhaps the noise

has something to do with the Alaska Triangle,

which is an area of Alaska that stretches from Juneau

to Anchorage to Utqiagvik.

And some of the things that are said to occur there

are energy vortexes and bizarre magnetic activities.

[humming]

- [Tony] McCarthy says a number

of unexplained incidents have occurred

in this geographic area that ended in tragedy.

- In 1950, a U.S. military plane

went down in the Alaska Triangle

and 44 people on board disappeared without a trace.

Then in October 1972,

a plane carrying two congressmen went down

in the Alaska Triangle and no trace of that plane

has ever been found either.

- [Tony] But McCarthy says

there's an even more nefarious idea

of what could be causing this strange mountaintop anomaly.

- Another theory is that this maybe is 5G.

5G is a wireless network that can be used

to transmit information over radio waves.

Some believe that 5G caused mass bird die-offs,

harm that has come to trees,

and some even believe that it can cause cancer

or other health issues.

[humming]

- The number of disappearances

within the Alaska Triangle is three times higher

than the national average.

Were our hikers experiencing the mysterious force

that's snatching planes from the sky?

Or perhaps they were caught in the crossfire

of allegedly dangerous 5G radio waves.

With all these mounting questions buzzing around,

my head is starting to buzz too.

Let's tune in to what our experts are saying.

- Given the extreme weather in Alaska,

you can actually get several inches of snow per hour.

So if there is a plane crash,

it's possible within a matter of hours

that it's completely covered by snow.

Something that goes missing in Alaska

is gonna be extremely difficult to find.

[humming]

- [Tony] So could our hikers have been intercepted

by supposedly harmful 5G waves?

- 5G does not have any visible or auditory effects,

simply because it's the wrong wavelength, frequency,

and amount of energy.

If they were able to do any sort of harm,

then so can visible light colors,

which contain significantly more energy.

- [Tony] So if it's not 5G and it's not

the Alaska Triangle, what's really going on here?

- I actually fear for the safety

of the individual in the video,

because what we're seeing is a

relatively common occurrence before a lightning strike.

[lightning crashing]

- [Tony] Hernandez explains

that cold weather conditions like those seen

in the video can cause a buildup of electric energy.

- It's possible that she is somehow interacting

with the electric field

in the area and creating a static electricity.

A lot of times when we feel static charge,

that usually means that

lightning is very close to striking.

- [Tony] Lightning occurs when electrical charges

in the air and on the ground reach a critical imbalance.

There's a moment before it strikes

when static electricity

is building in the air near the ground.

The rapid transfer of energy restores the equilibrium.

And Szydagis says this buildup of energy can create a sound.

- That buzzing sound can be created

by electricity, since sound

is simply caused by movement of atoms.

And if you have electrons within atoms moving around,

the atoms as a whole will be moving around,

and you actually can create sound,

which is simply changes in air density.

[humming]

- Our verdict?

This was simply a buildup of static electricity,

and a dangerous one at that.

But thankfully, our hikers made it out alive and well.

Alaska may be full of mysteries,

but this strange sound is no longer one of them.

but this strange sound is no longer one of them.

Generally, when people think of ocean sounds,

they think of something relaxing.

The marine noises in our next story are anything but.

Let's see why an entire commercial fishing team

was shaken by what they heard echoing across the waves.

August 2021, the North Atlantic Ocean.

A Massachusetts fishing vessel makes its way

through the night when the crew begins to hear

an eerie noise.

One of the fishermen pulls out his camera and records this.

- [Tony] The camera pans across the black ocean.

- [Tony] Then the haunting screams of something off

in the distance.

[screaming]

[screaming]

- When the video hit social media,

the first obvious theory was a whale song.

But many questioned if such sounds could ever be heard

this clearly above the water?

- [Tony] Eric Grunhauser says others speculated

that it was the cry of the legendary sirens

of Greek myth, whose song could seduce sailors

to their doom.

- With only 5% of our oceans

having been fully explored,

is it possible that sirens of Greek myth

are still out there on some lonely craggy rock waiting

to be discovered?

- [Tony] Another theory posits

that we might be hearing the sound of a haunted ghost ship.

And this isn't just a fisherman's tale.

- Ghost ships are a popular legend,

versions of which you can find all over the world.

- [Tony] In October 1931,

a 230-foot cargo ship called

the SS Baychimo became trapped in ice off Alaska.

Twenty-two men were rescued,

but 15 volunteered to stay behind,

hoping it would break free and they could save it.

These brave men were never seen again, but the Baychimo was.

- The workers thought that the Baychimo

had sunk, but a few weeks later,

some hunters actually spotted the Baychimo floating off

the coast of Skull Cliff.

Some six months later,

a dog sled crew actually saw the Baychimo in the sea ice.

- [Tony] The abandoned ship had broken free of the ice.

It stayed afloat for decades,

scaring the locals wherever it went.

- The ship was last seen in 1969 when it

was spotted by some coastal residents.

Could the sound in this video actually be

the haunted sounds

of the ghost ship Baychimo floating somewhere nearby?

- When it comes to ghost ships, nobody beats Japan.

For the past several years,

hundreds of boats filled with rotting corpses

have mysteriously washed up on western Japanese shores.

Spooky, right?

Items found on board led investigators

to believe these boats belonged to defectors

or desperate fishermen from North Korea,

all of whom lacked the proper supplies to survive.

Let's see what our experts think about this oceanic oddity.

- Even a trained opera singer would

have trouble making a frequency this high

from the soprano range.

[screaming] - Oh my God.

- [Tony] So he decides to test the sound

against something more mechanical,

exploring the possibility

that perhaps they were hearing another ship

or even their own.

- Comparing the sound to examples

of hydraulic machinery on a ship,

we have some similar frequency characteristics

and some plausible connection between the two.

[humming]

[screaming]

But we don't see an example that exactly matches,

so we can't really guarantee that the sound

in the example recording is from a mechanical source.

- [Tony] But before we say it's a mythical siren,

- Oh my God. - Shea Steingass brings

the conversation back to whales,

but not in a way you might expect.

- Alaska is known

as a biodiversity hotspot for whales.

[whale calling]

What I think we're hearing here has only been documented

in a couple dozen individuals

of humpback whales, specifically in Alaska.

And I think this might be an example

of collaborative feeding.

- [Tony] Collaborative feeding

is when whales use vocalizations and bubbles

from their blowholes to trap and stun fish for feeding.

But how can this be heard above water?

- The frequency

of sound doesn't actually change between water and air.

So we can hear noises and they would sound the same to us

on land or on a boat as they do in the water.

- [Tony] To double check this theory,

we had Rob Maher run humpback whale sounds

through his spectrogram.

And sure enough...

[whales calling]

- The recordings with a hydrophone underwater

of the humpback whale have very consistent frequency

with what's observed in the example recording.

[whales calling]

And characteristics of the sound seem to match up.

- Our verdict? Our experts agree.

What we are hearing is a very rare example

of humpback whale vocalizations.

But that doesn't mean there aren't any ghost ships

or sirens out there.

So make sure you're prepared to batten down those hatches.

- It's often said, if you have your ear to the ground,

you'll hear everything that people are saying and doing.

But as you'll hear in our next piece,

if you do that on Mars,

you'll be confounded with a cacophony of sounds

and mystified by their origins.

Some people say that the origin of this next sound,

recorded by NASA, was from a Martian civilization.

We say it's something you've got to hear to believe.

March 6th, 2019, around 2 PM local Mars time.

The 98th Martian day or Sol of the mission

for NASA's InSight lander.

The spacecraft is surveying its workspace.

A camera on its robotic arm is moving

and snapping pictures after placing a seismometer

on the surface to study Mars quakes.

While it finds many, it also detects this.

First, an eerie hollow noise,

followed by a series of dinks and donks.

[humming]

Then a howl, right out of a science fiction film.

[humming]

What could be making these strange sounds?

- NASA's research with Mars found overwhelming evidence

that Mars was a wet, green planet, very similar to Earth.

It had water, breathable air.

Many people think there was a civilization

that once lived there and is now extinct.

So perhaps we're hearing some type

of signals being sent out from Mars from the distant past.

Back in 1901, Nikola Tesla claims

that he had received radio signals from Mars.

So possibly this is the remnant of that communication

that we're hearing now.

[humming]

- [Tony] Another possibility, and go with us

for a minute, is that the sounds are emanating

from within some large underground structure.

- Some researchers believe that sound played

a major role in the architecture and the building

of the pyramids.

- [Tony] A passage was discovered inside

the Great Pyramid of Giza,

thought by some to function

as an acoustic resonance tube,

meaning it amplified sound vibrations

from the air outside,

generating infrasounds that some

claim can induce otherworldly sensations.

Could this have been a deliberate part

of the pyramids' design?

And could an alien race

have constructed something similar on Mars?

- There is no reason to think there couldn't

have been an advanced culture on the planet

that could produce structures that were similar.

And what we're hearing with these odd sounds on Mars

is the remnants of some structure

that's been buried beneath the surface.

[humming]

- The nature of Mars's atmosphere

means sound operates differently there.

In fact, sound travels 100 meters per second slower

on that planet than on Earth.

Additionally, there are two speeds of sound on Mars,

one for high-pitched sounds and one for low-pitched sounds.

Let's see if our experts can pitch in and tell us

what we're hearing here.

- I found the recording in question

on the NASA website,

so I believe this is a genuine recording.

- [Tony] Ed Primeau proceeds to compare the sound

to the first potential match, Mars quakes,

which are frequent and well-documented.

- The frequency range on the quake

is below 100 hertz across the board.

The recording in question goes up much higher

than that, about 400 to 1,000 hertz.

[humming]

So I can safely rule out this sound being a quake.

- [Tony] Next, Matthew Szydagis digs

into the extinct civilization signal theory.

- Some people have hypothesized

that this is some sort of alien we are hearing.

However, Mars has not been

what we would consider habitable for billions of years.

The Martian atmosphere is extremely thin,

and it doesn't have significant quantities of atoms

or molecules necessary for life.

For example, oxygen.

Even if we consider life forms

that don't require oxygen, such as anaerobic bacteria,

an advanced intelligent civilization existing on Mars

is very unlikely.

- [Tony] Szydagis says this also reduces

the possibility of the sounds emanating

from an ancient structure.

It would just be too old to survive till now.

- It is possible there are structures buried

under the surface of Mars, especially as it's a desert.

But this just seems very far-fetched to me,

and I think this is something else.

[humming]

- So what are we hearing on Mars' surface here?

- Because of the high technology of the seismometer,

that's what we're actually picking up here.

The vibration of the arm moving, wind blowing,

the sand around, the vibration

of those particles pushing across the soil.

That's what you're hearing in this recording.

- Our verdict?

Wind and the movement of the spacecraft itself.

While this NASA mission has provided great data

for scientists and even greater fodder for a ufologists,

it is expected to cease functioning

by the end of the year.

But not us.

We'll keep an eye and an ear and a seismometer out

for any more Martian discoveries.

From the lifeless deserts on Mars

to the skies above California

and into the uncharted trenches of the ocean,

we've investigated the echoes of the unexplained,

some rooted in nature, others defying all logic.

But one thing is certain, the more we uncover,

the more questions we face.

Thank you for watching the special edition

of "The Proof Is Out There".

Please send us any video,

images or sound that you think we should investigate,

and remember to keep those cameras rolling.

[upbeat music]