Ancient cultures around the world tell stories of strange objects witnessed flying in the sky. But are these tales fiction, or might people actually have seen craft descending from the heavens?

All over the world there are megalithic stone structures whose construction baffles archaeologists. Is it possible that humans managed to move these gigantic rocks with the help of alien technology?

A 2,000-year-old computer, a power plant inside the Great Pyramid, and a Nazi-era time machine. Could these devices be products of our ancestors' imaginations or might ancient man have had access to extraterrestrial technology?

Throughout history, there are stories of strange beings unlike anything known to exist on Earth. Could they be more than just mythology?

The Reptilian alien is a fixture of science-fiction, from HP Lovecraft's tales of Valusians to the Cardassians in Star Trek. Could ancient myths about reptilian creatures provide evidence that they are more than just a pop-culture creation?

One of the most prolific inventors of the 20th century, Nikola Tesla shepherded mankind to a new industrial era and laid the groundwork for today's technological age. Is it possible that he was influenced by some otherworldly design?

One of the most prolific inventors of the 20th century, Nikola Tesla shepherded mankind to a new industrial era and laid the groundwork for today's technological age. Is it possible that he was influenced by some otherworldly design?

It's been called the key to the universe and possibly the most important scientific breakthrough of all time. Could the so-called 'God Particle' reveal the truth about our origins?

It's been called the key to the universe and possibly the most important scientific breakthrough of all time. Could the so-called 'God Particle' reveal the truth about our origins?

Ancient Aliens explores the controversial theory that extra-terrestrials have visited Earth for millions of years.

From the beginning of recorded history there have been stories about beings with superhuman strength, super-sonic speed and supernatural abilities. Is it possible that these stories are based on extra-terrestrial beings that once lived on Earth?

From the beginning of recorded history there have been stories about beings with superhuman strength, super-sonic speed and supernatural abilities. Is it possible that these stories are based on extra-terrestrial beings that once lived on Earth?