If ancient aliens visited Earth, what was their legacy, and did they leave behind clues that exist in plain sight such as sophisticated aircraft, complex electrical grids, and intricate construction machinery?
Indian Sanskrit texts, dating back to 6000 B.C., describe in varying but vivid detail flying machines called Vimanas.
Megalithic stone structures in Egypt reveal evidence of precision saw work.
Are these examples of modern technology, or is there evidence that these incredible mechanisms existed on Earth thousands of years ago?





The Moai of Easter Island
The Polynesian island of Easter Island is famous for its “maoi”: the 887 giant human figures with enormous heads that guard its coastline. Roughly 500 years old, these monolithic statues stand 13 feet high and weigh 14 tons, but some are twice as tall and much heavier. How could human beings without sophisticated tools or knowledge of engineering craft and transport such incredible structures? Some ancient alien theorists believe it is the work of visiting extraterrestrials who left their mark on the island.




Pacal’s Sarcophagus
Pacal the Great ruled over the Mayan city of Palenque, in what is now southern Mexico, during the seventh century. Upon his death, he was buried inside a pyramid called the Temple of Inscriptions. The intricately carved lid of his sarcophagus has become a classic work of Mayan art—and an oft-cited piece of evidence for ancient alien theorists. In their view, Pacal is pictured in a spaceship during takeoff, with his hand on a control panel, his foot on a pedal and an oxygen tube in his mouth.



The Nazca Lines
Etched into a high plateau in Peru’s Nazca Desert, a series of ancient designs stretching more than 50 miles has baffled archaeologists for decades. Along with simple lines and geometric shapes, they include drawings of animals, birds and humans, some measuring more than 600 feet across. Because of their colossal size, the figures can only be appreciated from way up in the air—and there is no evidence that the Nazca people, who inhabited the area between 300 B.C. and 800 A.D., invented flying machines. According to ancient alien theorists, the figures were used to guide spaceships as they came in for a landing, and the lines served as runways.



Vimanas
Many Sanskrit epics, which were written in India more than two millennia ago, contain references to mythical flying machines called vimanas. Pointing to similarities between descriptions of vimanas and reports by people who claim to have seen UFOs, ancient alien theorists have suggested that astronauts from other planets visited India during ancient times.