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 ...

This is just one of many stories found amongst Soviet-era files that have been recently released to the public.

Striking images of bright “ red jellyfish ” appearing in the sky above storm clouds have sparked a wave of speculation online, with some social media users even floating theories about alien activity.

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