WATCH ONLINE, MOBILE, FREEVIEW 64, SKY 164, SKY GLASS / SKY STREAM 169, FREESAT 162 AND VIRGIN 174
Ancient astronaut theorist, Giorgio Tsoukalos, takes a look at evidence to support the theory that extraterrestrials visited Earth in the past. Explore some of the most intriguing finds that many believe are clues to our extraterrestrial past.
