Some of them wore wristwatches.

They had boots on and helmets and, above all, wings, and they were always described or depicted in floating above some “regular people.”

So the question is: who were the Anunnaki? And according to the ancient astronaut hypothesis, they were space travelers who visited Earth in the remote past. Similar themes can be found in the legends of Greek and Roman gods, which also describe events that some interpret as extraterrestrial contact.

Both cultures believed in powerful gods who lived in the heavens and often came down to Earth to interact with humans.

CHILDRESS: A well-known example is Zeus and the Greek gods, and they’ve come down from the sky and Mount Olympus, where they live in some mountain, and they’re bringing, really, civilization and sciences to mankind, but they have many human attributes, too, where, yeah, they, uh, they’re attracted to human women, uh, they want to have sex and children with as many of ’em as they can, and then they go back into the sky.

THOMAS BULLARD: These ideas of gods mating with humans are very commonplace, like Zeus in Greek mythology was always coming down, mating with mortals, and producing demigods like Hercules or Helen of Troy, who were exceptionally beautiful, exceptionally powerful, unusually gifted in every way. So, in other words, you were creating a better race in, in this sense.

TSOUKALOS: In the ancient astronaut opinion, the whole pantheon of gods that we have in ancient Greece consists of nothing else but flesh-and-blood extraterrestrials who were misinterpreted as being these divine creatures by our ancestors.

CREMO: There is a lot of evidence showing that we’re not alone in the cosmos and that our human civilizations on Earth have been interacting for long periods of time with extraterrestrial intelligence. Belief in celestial beings interacting with humans is a cornerstone in several major religions.

In fact, according to the Bible’s Book of Genesis, God created the first humans Adam and Eve. The Bible also contains other passages that describe strange interactions between “otherworldly” beings and humans.

CARGILL: People believe messengers of some sort come down from the heavens. You know, they came down and they had sex with humans, and this is where we produced giants, people like Goliath, so in a technical sense, they are alien. They’re gods or they’re angels; there’s some kind of superhuman thing.

Interpreting these Bible stories has also led to a certain amount of debate and controversy. While most see a single god directing and influencing mankind’s destiny, others argue that it is really a number of gods that are responsible.

TSOUKALOS: In the Old Testament, it says very clearly, “And then God created man in our own image. ” Now, grammatically speaking, that sentence doesn’t make sense, because you have “God” and then you have “our image. ” Well, theologians suggest that, by “our,” what they meant is the Trinity, the Holy Trinity, so basically, if you were to change the word “god” to “gods,” then all of a sudden, the sentence makes sense– “and then the gods created man in our own image.”

CARGILL: So you have this reference– “let us create man in our image.” In several religious texts, specifically the Hebrew Bible, which Christians also accept, and in the Koran, which Muslims revere as holy, you have the reference to God in the plural, and it is incredibly interesting.

But do all these religious scriptures that tell similar stories really point to the possibility that aliens have visited Earth throughout ancient history?

BIRNES: The fact is, the story of creation in our own Bible is the story of creation in cultures around the world.

The story of the flood, the evolution of the human species, the development of language– all of this points to– in fact, the Bible says so– life on Earth came from contact with an extraterrestrial life form. That’s in the Bible. That’s in ancient cultures around the world.

So I believe the theory of ancient astronauts is true, and I believe there’s solid evidence there, and I believe the harder you try to refute that evidence, the more you wind up against a brick wall. That ancient astronauts visited us, visited Earth thousands upon thousands of years ago, and seeded the very civilization we have today.

If the believers in the ancient astronaut theory are correct, then just who were these visitors? And might cutting-edge astrophysics and biology help us to uncover their identity? On March 18, 1965, Russian cosmonaut Alexei Leonov stepped outside the Voskhod 2 and became the first human to walk in space.

He spent 12 minutes and eight seconds outside his ship before returning. Leonov’s survival depended upon a protective suit that could keep him alive where there was neither atmospheric pressure nor oxygen.
If we need spacesuits, would aliens traveling to Earth require the same protection? Is that what we’re looking at in these ancient carvings and drawings?

TSOUKALOS: When critics ask, “Well, why would ancient astronauts have to wear astronaut suits like that we’re familiar with today?,” the answer is very simple.
Can we go through space without wearing a type of suit? Of course not. We would die. ‘Cause who says that whoever visited us in the remote past, that they could breathe in the atmosphere of planet Earth? So, it’s not farfetched to suggest that they did, in fact, wear some type of suit.

Why might these images resemble modern astronauts? If they are aliens, is it possible they are similar to humans? And could they have come from a planet just like Earth? At the turn of the 20th century, a group of British and German scientists considered this possibility.

They embraced a theory put forth by early Greek philosophers, that all life in the universe began in one specific place. This theory is called panspermia.

SEAGER: Panspermia is the theory that life formed in one place, and then got spread around to other places. In outer space in the medium between stars, we see molecules that are the building blocks of life.
So it’s easy to get the building blocks of life to another planet. For example, if life formed on Mars, it could have come here to Earth, contaminated Earth, and then started life here.

Roughly 36 billion years ago, Mars was warm and wet, much like the conditions on Earth today.

Biologists believe that because Mars cooled more quickly than other planets, life may have developed there first.

PAUL DAVIES: Mars is a better candidate for life during the early part of the solar system. Mars rocks are coming here all the time, and these have been knocked off Mars by asteroid and comet impacts.
And we know that they could convey any Martian microorganisms to Earth.

In August 1996, a team of scientists made a stunning announcement. A Martian meteorite found in Antarctica contained evidence of fossilized life. The four-pound rock, designated ALH 84001, showed the presence of carbonate globules excreted by microbes when they were alive on Mars 36 billion years ago.

Earth was no longer alone. Life had existed elsewhere in the universe.

DAVIES: So this cross-contamination between Mars and Earth, which 20 years ago was regarded as a rather wild conjecture, is now pretty much accepted by the astrobiology community.
Astrobiologists studying the origin and evolution of life in the universe embraced the possibility that life on Earth began in outer space.

Did modern-day scientists finally prove what ancient cultures have believed for centuries?

BAUVAL: The common myth or idea that the origins of humankind is from the stars is widespread. Ancient cultures have The ancient Egyptians, the Mayans, the Aztecs, the Indians and so forth Uh, is intriguing, and it’s probably true. And I mean it from an astrophysical point of view. We do come from the stars.

It’s a fact that life on earth has been seeded by the coming of a comet containing the life matter.

SCHOCH: I personally suspect there is life out there. In fact, I believe that we have evidence if nothing else, microbial evidence, for life extraterrestrially.

But if life did land on Earth from outer space, was it by accident, or might it have been sent here on purpose? One mainstream scientist thought so.

British geneticist Francis Crick is best known for his collaboration with James Watson. Together, they unraveled the structure of human DNA in 1953.

Less than ten years later, they were awarded the Nobel Prize for their groundbreaking work in genetics. In the 1960s, Crick became a proponent of panspermia theory and took it to a whole new level with an idea he called directed panspermia.

GRAHAM HANCOCK: Francis Crick hypothesized that somewhere, perhaps on the other side of the galaxy, there had been a civilization of advanced intelligent beings.
And they had found that their planet was going to be destroyed.

Perhaps a supernova was going to go off in their vicinity, and their planet would be sterilized of life.

And he asked himself, “What would an intelligent civilization do in that situation?” Um, well, first of all, they’d try to figure out if they could get out of there if they could actually preserve their lives and the lives of their descendants.

Perhaps crowd into spaceships and fly across interstellar space until they found a suitable planet to colonize. But could it actually be true? Could we really be the descendants of an alien race that traveled here from another world?

POPE: The ultimate implication of some exobiological theories is actually that we ourselves are extraterrestrials, that life on earth arose because the organic material was brought here from elsewhere.

BIRNES: What if we’re the ones, the descendants of those who came from another planet?

We weren’t created.

We were brought here, seeded planet Earth as a colony from some other planet. So we’re colonists of another race. And that’s why the aliens look like us.

SCHOCH: In my opinion, it’s not unscientific to consider the possibility of ancient astronauts, alien intervention. We live in a huge universe. Now, bacteria versus humanoids– one may say, that’s a big difference, but in some ways, it’s not a big difference. Where you have life, you have the ability for that life to develop into what we consider civilization or intelligent beings. Is it just a coincidence that modern science and ancient alien theory have come to the same conclusion: that life on Earth came from the stars?

And if it’s possible that billions of years ago, an extraterrestrial race spread out across space, how would they survive in their new home? Could they really be our missing link? For thousands of years, mankind has tried to depict alien beings who they believe came from the skies. Many of those creatures seem to share characteristics with humans.

They often have two arms, two legs, fingers and a head just like we do. Biologists refer to this basic body shape as bilateral symmetry.

MICHAEL DENNIN: Bilateral symmetry is, very simply, you divide something down the middle into two parts, and lateral means up and down, and the two sides are an exact reflection of each other.
If you fold the thing in half, all the parts line up.

RUSSELL TUTTLE: Being bilaterally symmetric allows you to be streamlined and to develop a head end, so you become cephalized.
And that certainly happened in vertebrates.

Virtually, the mouth at the end of something and then you get progressive development, and that seems to have led to many, many advances. (creatures chirping, chittering) DENNIN: So, when you look at it closely, you can see a lot of advantages coming in. Having the two arms and two legs to work together really gives you great mobility and balance and speed. Having eyes on two sides separated gives really improved vision in various ways.

Animals that are predominantly prey use their two eyes independently and get a huge field of view. Animals that are predominantly hunters have them more in the front and get really good depth perception, which you need if you’re gonna land on the animal you’re hunting.

If it is true that aliens resemble humans in their physical characteristics, might there also be genetic similarities? Could we even be related?

In 2003, the U.S. Government announced that the Human Genome Project had identified all of the nearly 25,000 genes in the human body. For the first time, scientists had a roadmap to the genetic make-up of humans.

In 2006, genetic researchers at the University of California at Santa Cruz discovered an area of the genome they called HAR1 that appears to be unique to humans. Scientists believe the HAR1 gene plays a critical role in the advanced development of the human brain and is a key element that sets us apart from other animals.

But where did it come from? Did humans develop this distinct gene naturally through evolution? Or did it land here from another planet? Francis Crick, the British scientist who helped discover the structure of DNA, believed that human genes could not have evolved by chance.

HANCOCK: Crick didn’t feel in that period of roughly formation of the planet down to the time when the planet could first support life, there was enough time for DNA to evolve by accident.
It’s an enormously complicated molecule.

Crick gave this analogy: You would be more likely to assemble a fully functioning and flying a jumbo jet by passing a hurricane through a junkyard than you would be to assemble the DNA molecule by chance in any kind of primeval soup in five or six hundred million years. It’s just not possible.

But if this molecule could not have evolved accidentally, how was it created? Was it, as some believe, put there on purpose?

TSOUKALOS: The question should not be, do the extraterrestrials look like us or what do the extraterrestrials look like, but do we look like the extraterrestrials?

Because according to the ancient astronaut theory, a long, long time ago, extraterrestrials came here, and through a targeted mutation of our genes, we– quote, unquote– “became human.”

FIEBAG (translated): Possibly there is information in our DNA about whether human evolution was manipulated or not. The DNA is almost deciphered, yet we only understand five percent of the information it carries.

TSOUKALOS: Geneticists have determined that it only takes about five percent to clone a human being, and that that we have in our bodies is nothing more than what they refer to as “genetic junk.”

DENNIN: Why is everything there? And there’s probably parts of the DNA that don’t have an obvious current function. Maybe they’re left over from something that was used in the past, kind of like our appendix is left over.

Could this “genetic junk” hold the key to the evolution of humans? Some people suggest that decoding our DNA entirely will unlock startling information about our origins. But could it even prove that aliens played a role in our development thousands of years ago?

HANCOCK: If you hypothetically wanted to record an eternal message that could be decoded by a creature that had eventually evolved enough intelligence to decode it, the place to put that message would not be on some monument or in some text, which might be swept away, but actually on the DNA of the creature itself. (baby cooing) It’s recently been established that DNA is a recording medium of almost limitless power.

It would be technically possible to record the entire knowledge of a civilization on the DNA in our bodies. All you’d need is a way to access that information.

VON DANIKEN: I think we have something, the whole humanity, in our genes. Somewhere in our genes, it is coded that extraterrestrials were here thousands of years ago. But the questions persist: If aliens visited Earth tens of thousands of years ago how did they get here? When we look to the past for the answers, are we looking in the wrong place?

Should we actually look forward to our future? Scientists agree that the best chances of finding alien life will be on planets similar to ours, and descriptions of extraterrestrials seem to resemble humans in many ways. Some ancient astronaut theorists draw a surprising conclusion from these facts, suggesting that aliens might actually be human.

POPE: It is odd that many of the descriptions of aliens are effectively humanoid, and this raises an interesting possibility. One idea that’s been put forward is that, uh, these are not extraterrestrials at all, but they’re time travelers from the future.

NOORY: They could be us from a thousand, 2,000, 10,000 years from now. Let’s assume for a moment that planet if we all survive, that time travel was created. They’ve invented it. Just like the time machine of H.G.
Wells’ day, they can go back, or they can go forward.

So let’s assume 10,000 years from now we decide to come back to see us. Maybe they have changed physically. They look like the alien grays or whoever they may be.

BIRNES: It could well be that ancient astronauts might not be creatures from other planets at all, but time travelers from 2720 in a time machine.

Time travel is an essential concept for science fiction, but would it be possible for flesh-and-blood humans to find a way to transport themselves through time with current technology? Would this enable us to cover the vast distances of space?

PAUL DAVIES: If I could travel close to the speed of light, I could reach the year Have to get very close to the speed of light for that, but it’s doable, and we know that this isn’t a theory, this is this is real physics– we could demonstrate these time-warping effects. So you can reach the future quicker by traveling close to the speed of light.

The concept of time travel was first proposed by Albert Einstein in 1905 when he published his Theory of Special Relativity.

DENNIN: Ancient astronaut theory says that astronauts visited us a long time ago from somewhere else. The technology involved in doing that, we would assume would be similar to what we understand now.
I mean, we know special relativity is a law of physics.

It holds anywhere in the universe. Ancient astronauts that would come all the way here can travel these large distances and not age that much, relative to their home planet.

Because if you’re going close enough to the speed of light, you will have slowed down time enough that when you get back, hundreds, thousands, or even millions of years could have passed. One limitation to this method of travel is that because a spacecraft has mass, it theoretically cannot reach the exact speed of light.

The resulting reduction in velocity would then dramatically increase the amount of time needed to cross the vast universe.

NOORY: Well, there’s definitely many theories about how extraterrestrials got here, how their propulsion system got them to planet Earth. They’re surely not coming here the way we go out into space. They’d never get here. They are finding different ways. They have either developed a new form of propulsion, or they’re able to travel through– what I’ve always believed– wormholes throughout the universe. That would instantaneously put them here.

The idea of wormholes was first proposed in longtime collaborator Nathan Rosen. They began to explore the possibility that space and time could literally be bent to create a time travel shortcut.

DENNIN: Wormholes have not been detected. They are a postulated structure in space that involve actually taking– if you want to think of a sheet of paper– bending it in half and connecting the two pieces that you get together. A wormhole is thought to do something like that. Space gets warped, and it connects between two different parts of space. You know, there are predictions about what they would look like; there are theories about them, but we haven’t detected one yet.

You’re not actually ever traveling faster than the speed of light; you’re just cutting corners.

CHILDRESS: You don’t actually have to go light speed and travel for light-years to someplace. You literally go there through a wormhole and through hyperspace, and bang, you’re there.

DAVIES: If you can have a wormhole in space, then it can be turned, in principle, into a time machine. And so travel back in time as well as forward in time would then be possible.

The problem is: where do you get your wormhole? Uh, it’s not inconceivable that wormholes were made in the Big Bang, coughed out along with everything else, and there might be one out there in the universe we could harvest or adapt to form a time machine.

DENNIN: If you end up discovering that you could make wormholes, then that increases the range that you can explore in space and that increases the likelihood of having two civilizations at the same time with the right technology to communicate with each other. While theoretically possible, traveling through wormholes or at the speed of light is currently both economically and technically impossible for us here on Earth. Using modern propulsion methods, it would take 70,000 years to reach the nearest star.

DAVIES: Our fastest rockets are totally puny. It’s really pathetic. So we’re talking about luck. Any object that we can fire out into the solar system is going to take tens of thousands of years to reach the nearest star. Believe it or not, at 4. 6 billion yrs old, our solar system is one of the youngest in the universe.

But if civilizations exist in other galaxies, is it possible that they are more advanced than those on Earth? And if so, could they be ahead of us in their ability to travel through space and time?

CHILDRESS: For extraterrestrials to come here, through the vast reaches of space to our planet, they clearly have to have technology that’s way in advance of what we have today.

To go from solar system to solar system, rather than going warp speed, like in Star Trek, you really are going to travel, as they do in Star Wars, where you’re jumping through hyperspace.
Going from a solar system to solar system is no time at all.

TSOUKALOS: Just because we can’t travel from star to star does not mean another more advanced society can’t do it either. I think that’s the height of human arrogance to say, “Just because we can’t do it, another more advanced civilization can’t do it either,” so, you know, we have to stop looking at us that we are the pinnacle of creation ’cause we’re not. Celestial beings. Visitors from the skies.

Deities descending from the heavens to interact with man. Could these worldwide stories be the foundation for the prevailing belief that something greater than ourselves, from beyond our world, created the universe as we know it? Almost all of the great world faiths are based on stories of celestial beings who visit Earth.

Many millions of people accept these legends as part of their core beliefs. And from the earliest cave drawings to images at Roswell, we see artists’ interpretations of extraterrestrials or gods coming to our planet.

YOUNG: In many traditions, there is something coming from above. There is a stairway to heaven or there’s a whirlwind or an angel descends. Sometimes the encounter is quite dangerous. As would be appropriate to something awesome and larger and more powerful than we are. Usually, it is memorable.

CHILDRESS: Many of the myths are much more specific and they really talk about gods physically coming to Earth– landing, doing miracles and showing the people how to live.

If visitors did come from the stars, is it possible that they actually changed the way ancient people thought?

Did they provide an intellectual spark to prehistoric civilizations? Could that be the reason why so many different cultures could build such large and lasting monuments?

NOORY: It’s almost as if the primitive man woke up one morning and went, “Hey, I’ve got this knowledge and I know how to make tools and I’m gonna go and build all these things.” Nah, I don’t think it happened that way. I think others came down to this planet and started teaching other people, uh, that were beginning to evolve.

But the one thing I truly do not believe is that modern cavemen at the time basically created all this knowledge out of thin air.

TSOUKALOS: All around the world, we have concise descriptions in ancient texts which say word for word that some beings came from the sky. So it’s as if this intellectual Big Bang or this Big Bang of knowledge occurred in various periods of time, and those various periods of time most concisely always correlate with some type of description of gods descending from the sky.

HANCOCK: I do think of that as a very significant before-and-after moment in the human story, and it is not a moment that is linked to physical evolution.bWe’ve already got the hardware. It’s as though something happened to our software around about that time, and I think it’s a very intriguing moment in the human story. For supporters of ancient alien theory, the verdict is already in.

They believe that aliens visited many of Earth’s earliest cultures thousands of years ago.

But is it possible? Are extraterrestrials responsible for the sacred creation myths of the first human civilizations?

Might they have tampered with our DNA? Are humans themselves aliens from another planet in the heavens or even from another time?

While man continues to search for these answers, the questions remain. If they came here, what was their mission? We call Earth home, but with perfect conditions for life, could it be a beacon, calling out to other intelligent civilizations that may exist in the universe?

CARGILL: I think there is life, simple life, bacterial life, microbial life on other planets. I think we’re going to find that. And who knows?

Maybe one day we’ll find some other planet that’s capable of sustaining life, that has evolved people over a long period of time, that are also looking up at the stars wondering: is there anybody else out there, are we the only ones?

HELDMANN: What bigger question could we ask about ourselves and our place in the universe? You know, is there life elsewhere in the universe, or are we it? I mean, I think it’s one of the most fascinating questions, and we’re fortunate enough to live in a time when we can address this question scientifically and really try and get at some answers.

NOORY: You can then come up with a conclusion that something, one, very strange is happening on this planet, and two, if it’s coming from outside of this system, then we’re being visited by something that has some intelligence behind it.

TSOUKALOS: In the end, the truth wins, and we’ve seen this in history, where scientific theories or ideas that have been deemed impossible turned out to be true, and so it is my firm conviction that the same will count for the ancient alien theory.