BBC News Story; says:It's 60 years since the term flying saucer was coined and the most celebrated "extraterrestrial" episode - Roswell. Alien believers are dismissed as cranks, but even the earthly explanations of objects in the sky are fascinating.
Sixty years ago Kenneth Arnold saw something which changed his own life, the life of millions of others and impacted on popular culture like a shockwave. Flying his plane near Mount Rainier in US state of Washington he observed a line of strange objects either crescent-shaped or disc-like, flying with the motion of a saucer skimming on water. Arnold's sighting, quickly picked up by the press, was followed a fortnight later by the revelation of perhaps the most notorious episode in the history of UFOs, at Roswell in New Mexico.
Having announced it had recovered a "flying disk", the Army airfield backtracked and referred only to a weather balloon.
What followed was perhaps one of the greatest conspiracy theories of all time, involving post-mortem examinations of swollen-bellied grey aliens, the cloning of sophisticated extraterrestrial technology and an epic cover-up. Or not, as the case may be.
In the 60 years since 1947's first major wave of sightings, thousands of ordinary people have claimed to have seen inexplicable objects in the sky.
When the Ministry of Defence released papers on its own investigations into the phenomenon in 2006, it was revealed more than 10,000 eyewitness accounts had been collected.
And for every sceptic who prefers explanations of weather balloons and freak atmospheric conditions there is someone who genuinely believes intelligent life is visiting the planet.
