Across the globe, archaeologists have uncovered ancient tombs filled with strange items and writings. Remarkable similarities have been found at each of the sites. How is it possible that the burial chambers of distant cultures were so similar in design? Ancient Astronaut theorists believe that some of these complicated and technically advanced tombs were designed with the help of extraterrestrials.

They were the messengers of divine knowledge and seers who shared visions of the future. For thousands of years, human civilization has been guided by the words and deeds of ancient prophets, but just who - or what - were these prophets communicating with? Might the experiences of history's prophets be evidence of communication with a heavenly source - or were seers like Elijah and Joseph Smith actually communicating with extraterrestrial overlords? And if so, are there similar prophets at work today?

Erich von Daniken's landmark book, Chariots of the Gods, brought attention to the mysterious phenomena of the Nazca Lines. Hundreds of gigantic lines, some in the shape of animals, geometric patterns and even an alien-like being, extend for miles throughout a remote Peruvian desert. Scholars are divided as to who built them, and why. Some Ancient Astronaut theorists believe that the massive markings have an extraterrestrial connection, and perhaps the ancient people of the region created these gigantic figures in tribute to the gods who visited them. And with one of the largest deposits of nitrates in the world - a key ingredient in rocket fuel and weaponry - could Nazca have been a mining operation for advanced beings in the distant past?

In 1975, Travis Walton claims to have been abducted and taken aboard a space ship inhabited by extraterrestrial beings. Several people witnessed his encounter and nearly 40 years later Walton's story of alien abduction, missing time and mind-telepathy manipulation has not wavered. But researchers say that abductions are not a modern phenomenon. The Hebrew Bible is filled with stories of abductions by otherworldly beings. Jonah, Moses, Ezekiel and Enoch all depict what can best be described as physically being taken to other dimensions and then returned. Is it possible that extraterrestrial beings have been abducting humans for thousands of years and if so, might there be an alien agenda behind the phenomena?

Examining author Erich von Daniken's controversial theories about alien life.

Examining a theory that aliens helped guide Viking voyages.

Exploring a potential link between ancient monoliths and extraterrestrials.

The ancient Egyptian design of the three pyramids of Giza; diverse cultures worship the all-knowing triads; an ancient tablet noted the power of the number three; the language of human DNA is written in a pattern of threes.

Luminous relics in the shape of human skulls. Otherworldly artifacts believed to harness the secrets of the universe. Are the Crystal Skulls part of an elaborate hoax? Or do they possess a great, perhaps even otherworldly power?

In ancient Mesopotamia, the Sumerians make advances in agriculture, science, medicine, and astronomy, crediting these achievements to winged gods known as the Anunnaki.

Wondrous wizards... Mysterious sorcerers... And heavenly beings... possessed of unimaginable power. Throughout the ancient world, magic was used for everything from healing to communicating with the gods. But did magic really exist in the ancient times? Not as a form of theater - but as a means of replicating the power of the gods? Do ancient accounts of magic suggest evidence of advanced, otherworldly knowledge? A knowledge given to early humans as a means of helping them unlock their own - some might say "divine" - potential?

He is the evil one, the Prince of Darkness, the ruler of Hell. Satan conjures up horrifying images of a horned beast whose sole purpose is to destroy humanity. Yet there is evidence that the fallen angel we know as Satan may be misunderstood.

Mysterious surgeries performed by early humans... Strange beings with miraculous powers... And a cover up - destroying centuries of scientific knowledge. Are recent breakthroughs in medicine the result of years of research?

Powerful monarchs ruling by divine right. Centuries-old dynasties amassing enormous wealth. And legendary leaders wielding powerful weapons of mass destruction. Is it possible that ancient rulers were, in fact, connected with divine or, some would say, extraterrestrial forces? And, if so, what was their purpose? Ancient emperors, kings, and pharaohs were often attributed with otherworldly strength, ability, and wisdom; many were even considered gods by the people they ruled. Who were these exceptional leaders, and how did some accomplish so much in their time? Ancient Astronaut theorists believe that these great rulers throughout history were "chosen" and guided by extraterrestrials. Is it possible that the world's legendary leaders might have shared a common genetic trait? A so-called, "leadership gene"? And might this gene have been - not a product of genetic evolution - but inherited by mankind from some otherworldly source?

Sacred bones... Golden hats... And fragments of sacred objects thought to possess healing properties. All around the world, archaeologists have uncovered mysterious relics revered by ancient cultures for thousands of years. Now on display in museums, temples and churches, millions of people travel great distances just to be in their presence. What is it about these ancient objects that draws people to them? Could the truth of mankind's origins be found in the fabric, metal, stone and bones of our distant past? And could these mysterious relics really provide us with the ability to access divine or otherworldly power?