The Pentagon releases scores of UFO files with reported sightings of spheres, discs and fireballs spanning nearly 80 years.

The US has recovered four distinct species of extraterrestrial life from crashed UFOs, a former CIA-funded government researcher sensationally claimed this week. Dr. Hal Puthoff, former Advanced Aerospace Weapon System Applications Program advisor and CIA-funded researcher,

The Pentagon's release of files might help scientists shed light on unexplained phenomena and government secrets, experts said.

The new Pentagon website includes 162 declassified files on UFOs, or unidentified aerial phenomena. Some experts wonder if they contain anything new.

A well-known conspiracy theory (also seen in The X-Files) attests that aliens are in communication with the U.S. government, providing knowledge and advanced weaponry, or engaged in secret wars with the military.

Rep. Tim Burchett told Piers Morgan aliens exist, pointing to government briefings, pilot testimony and video evidence shown to him by officials as proof.

The former president on why those waiting for Trump to disclose the existence of aliens are sure to be disappointed, and insisting first contact "hasn't happened yet."