Did a biblical patriarch receive instructions from 200 angels high above the earth? Were the ancient Greeks taught how to work metal by a race of fish-people? And might Egypt's most controversial pharoah have been an extraterrestrial being?

Ancient Astronaut Theorist Giorgio Tsoukalos takes a look back at The Top Ten Extraordinary Creatures we've investigated creatures that just might provide compelling evidence of extraterrestrial visitation.

Ancient Aliens is counting down the top ten locations around the world that might be hiding alien bases, including a cavern beneath the ice of Antarctica, a lake in China that is a hotspot for UFOs, and a pyramid under the slopes of Mt. Denali.

Counting down the top 10 scariest encounters that just might be evidence of extraterrestrial visitation.

Counting down 10 intriguing symbols and codes found across the globe that might contain proof of otherworldly contact.

Ancient Aliens is counting down the top ten most devastating disasters ever documented that might have an otherworldly connection.

The ancient Sumerians established what is considered the world's first civilization, and they credited their extraordinary achievements to their gods, the Anunnaki.

For years, Scotland has been an epicentre of otherworldly phenomena. It is home to ancient stone circles, stories of strange beings and a major hotspot for UFO sightings.

Along the Earth's north 37th parallel there have been so many reports of UFO's and other mysterious events that it has been dubbed The UFO Superhighway.

There are mysterious ancient stones shaped into perfect spheres. Many of them show clear evidence of being manmade and some completely defy explanation. Could the mystery of the stone spheres provide clues about humankind's alien past?