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.

Donald Trump's declassified UFO files and the documentary Sleeping Dog reignite the debate on extraterrestrial life, yet officials maintain no evidence confirms alien existence.

One investigator claims the slow drip of UAP disclosures is building towards a major moment for the public.

No bombshells so far in the latest Pentagon batch of declassified Unidentified Anomalous Phenomena files. But they show the CIA hid its involvement.

UPDATE 3-Trump releases government UFO files, more expected