Alien and UFO Documentary - Most Famous UFO Sightings in History

On the 30th anniversary of ET, Stylist looks for answers to the question - is there anybody out there? From alien abductions to lights in the sky and mysterious flying objects, here are 20 of the world's most talked-about UFO sightings...

Ranking as one of the most famous UFO incidents in history - and now a pop culture phenomenon - the Roswell incident saw UFO hunters claim that the US military had captured an alien aircraft. While the military maintain that the 'flying saucer' was actually a surveillance device from a classified operation, non-believers still cite extra-terrestrial activity to this day.

Kenneth Arnold case, 1947

Newspapers had a field day with Kenneth Arnold's story, even coining the term 'flying saucer', after the American businessman and pilot claimed he'd seen nine saucer-like objects flying in a chain near Mount Rainier in Washington.