Plunge headlong into the greatest alien mysteries of all time in this special ANCIENT ALIENS two-disc set from HISTORY. This provocative series explores the possibility that advanced technologies such as lasers and even gravity manipulation devices enabled ancient humans to construct colossal structures throughout the world. Many of these unexplained structures show engineering techniques thought to be unknown at the time. Might these technologies have come from distant galaxies? Or were the ancient builders really extraterrestrials? And, thousands of years later, did the Nazis experiment with similar advanced alien technologies? Well also consider whether contemporary rituals believed to connect humans to another dimension are based on ancient experiences with aliens. Through 75 million years of the most credible evidence available on earth, HISTORY entertains these and many more spectacular prospects.