If extraterrestrials influenced human history, can evidence of their existence be found in hidden tunnels and caverns around the world? Could a cave in Ecuador contain metallic books inscribed with secrets of alien technology? Was an ancient undergro... (more)und city in Turkey built with alien help... or as a refuge from an alien attack?

Bill Birnes, David Childress, David Wilcock, Erich von Däniken, George Noory, Giorgio A. Tsoukalos, Jason Martell, John Brandenburg, Linda Moulton Howe, Philip Coppens