Landmark UFO documents smuggled out of Russia 30 years ago — and just publicly revealed — show the Soviets investigated thousands of reports of extraterrestrial craft and encounters with aliens.

A 'jellyfish' UFO crowned by shifting coloured lights hovered above a Russian city for an hour before disappearing in the 1980s. The strange case is among a newly shared bundle of Soviet-era documents ...

Newly published documents detail investigations into strange aerial phenomena, including several close encounters ...