The series explores the controversial theory that extraterrestrials have visited Earth for millions of years. From the age of dinosaurs to ancient Egypt, from early cave drawings to continued mass sightings in the US, each episode in this new series gives historic depth to the questions, speculations, provocative controversies, first-hand accounts and grounded theories surrounding this age old debate. Did intelligent forms from outer space visit Earth thousands of years ago? Do they visit us now? HISTORY ignites this inquiry.