Chariots of the Gods?
The author theorized that extraterrestrials visited Earth in the past and their technologies were used by ancient civilization.
Chariots of the Gods? Unsolved Mysteries of the Past, written by Erich von Däniken, was published in 1968. Von Däniken brings forth the idea that ancient civilizations may have been contacted by extraterrestrials who may have recognized them as gods. The aliens could have introduced technologies that advanced these cultures. To support these ideas, Von Däniken uses artwork, ancient structures, and religions.