What if life on Earth began in outer space? Millions of people accept the theory that intelligent life forms visited Earth thousands of years ago and were worshiped as gods by primitive man. Are monuments like Stonehenge and Easter Island the last remains of an ancient alien visitation? From unexplainable super structures, to knowledge of the solar system, mathematics, and even the ability to make electricity, this special explores evidence of super-human influences on ancient man and embarks on an around-the-world search for answers. It's an investigation into a theory some believe cannot be true, but many agree cannot be ignored.

All over the world there are megalithic stone structures whose construction baffle stonecutters, scientists, and archeologists.

A 2,000-year-old computer... a power plant inside the Great Pyramid... and a Nazi-era time machine with roots in the ancient history.

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

Three ancient artifacts that could turn the history of the world upside down: In Mexico, a bizarrely-shaped skull may prove aliens once walked the planet; ancient stone carvings of dinosaurs could rewrite the story of evolution; and, an ancient wooden model may be proof that ancient Egyptians invented modern flight.

Ever since Plato first wrote about the mysterious island of Atlantis, it has captured the imagination of adventurers and academics alike. Was Atlantis merely a myth, or could it have actually existed in the remote past? Did Atlantis just disappear as Plato described? And could it have been the home of an advanced civilization that created the human race? Ancient Astronaut Theorist Giorgio A. Tsoukalos explores the most recent discoveries related to the centuries old story of Atlantis. By investigating a series of clues, Tsoukalos endeavors to narrow down the possible location of Atlantis. Could evidence be found in a strange egg-shaped stone in Portugal? What secrets can be uncovered on the island of Santorini, Greece? Could Atlantis have been an empire with a network that stretched around the world? Or was it something else entirely? Something that, perhaps, came from the stars?

The ancients believed that the universe consisted of countless worlds we could not see, and argued endlessly over the nature of these distant, invisible planets and whether they might be inhabited. Until recently many scientists thought we would never discover the truth, believing that extra-solar planets were simply too far, too small and too dim to detect. But new technologies have suddenly revealed thousands of distant planets, opening up the most exciting period in astronomy in decades. Some believe we're on the verge of answering the ancient question: are we alone in the universe?

What if life on Earth began in outer space? Millions of people accept the theory that intelligent life forms visited Earth thousands of years ago and were worshiped as gods by primitive man. Are monuments like Stonehenge and Easter Island the last remains of an ancient alien visitation? From unexplainable super structures, to knowledge of the solar system, mathematics, and even the ability to make electricity, this special explores evidence of super-human influences on ancient man and embarks on an around-the-world search for answers. It's an investigation into a theory some believe cannot be true, but many agree cannot be ignored.

All over the world there are megalithic stone structures whose construction baffle stonecutters, scientists, and archeologists.

A 2,000-year-old computer... a power plant inside the Great Pyramid... and a Nazi-era time machine with roots in the ancient history.

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

Three ancient artifacts that could turn the history of the world upside down: In Mexico, a bizarrely-shaped skull may prove aliens once walked the planet; ancient stone carvings of dinosaurs could rewrite the story of evolution; and, an ancient wooden model may be proof that ancient Egyptians invented modern flight.

Ever since Plato first wrote about the mysterious island of Atlantis, it has captured the imagination of adventurers and academics alike. Was Atlantis merely a myth, or could it have actually existed in the remote past? Did Atlantis just disappear as Plato described? And could it have been the home of an advanced civilization that created the human race? Ancient Astronaut Theorist Giorgio A. Tsoukalos explores the most recent discoveries related to the centuries old story of Atlantis. By investigating a series of clues, Tsoukalos endeavors to narrow down the possible location of Atlantis. Could evidence be found in a strange egg-shaped stone in Portugal? What secrets can be uncovered on the island of Santorini, Greece? Could Atlantis have been an empire with a network that stretched around the world? Or was it something else entirely? Something that, perhaps, came from the stars?

The ancients believed that the universe consisted of countless worlds we could not see, and argued endlessly over the nature of these distant, invisible planets and whether they might be inhabited. Until recently many scientists thought we would never discover the truth, believing that extra-solar planets were simply too far, too small and too dim to detect. But new technologies have suddenly revealed thousands of distant planets, opening up the most exciting period in astronomy in decades. Some believe we're on the verge of answering the ancient question: are we alone in the universe?

What if life on Earth began in outer space? Millions of people accept the theory that intelligent life forms visited Earth thousands of years ago and were worshiped as gods by primitive man. Are monuments like Stonehenge and Easter Island the last remains of an ancient alien visitation? From unexplainable super structures, to knowledge of the solar system, mathematics, and even the ability to make electricity, this special explores evidence of super-human influences on ancient man and embarks on an around-the-world search for answers. It's an investigation into a theory some believe cannot be true, but many agree cannot be ignored.

All over the world there are megalithic stone structures whose construction baffle stonecutters, scientists, and archeologists.

A 2,000-year-old computer... a power plant inside the Great Pyramid... and a Nazi-era time machine with roots in the ancient history.

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

Three ancient artifacts that could turn the history of the world upside down: In Mexico, a bizarrely-shaped skull may prove aliens once walked the planet; ancient stone carvings of dinosaurs could rewrite the story of evolution; and, an ancient wooden model may be proof that ancient Egyptians invented modern flight.

Ever since Plato first wrote about the mysterious island of Atlantis, it has captured the imagination of adventurers and academics alike. Was Atlantis merely a myth, or could it have actually existed in the remote past? Did Atlantis just disappear as Plato described? And could it have been the home of an advanced civilization that created the human race? Ancient Astronaut Theorist Giorgio A. Tsoukalos explores the most recent discoveries related to the centuries old story of Atlantis. By investigating a series of clues, Tsoukalos endeavors to narrow down the possible location of Atlantis. Could evidence be found in a strange egg-shaped stone in Portugal? What secrets can be uncovered on the island of Santorini, Greece? Could Atlantis have been an empire with a network that stretched around the world? Or was it something else entirely? Something that, perhaps, came from the stars?

The ancients believed that the universe consisted of countless worlds we could not see, and argued endlessly over the nature of these distant, invisible planets and whether they might be inhabited. Until recently many scientists thought we would never discover the truth, believing that extra-solar planets were simply too far, too small and too dim to detect. But new technologies have suddenly revealed thousands of distant planets, opening up the most exciting period in astronomy in decades. Some believe we're on the verge of answering the ancient question: are we alone in the universe?