In 1974, residents of an area of North Wales around Bala and Llandrillo were shaken by what seemed to be an earthquake, accompanied by flashing lights in the Berwyn Mountains. Both the lights and the earthquake were proven to have their origins in objective reality, but over subsequent years stranger tales have been spun from the memories of those who bore witness to those undoubtedly uncommon and bewildering events.
That evening has now taken on a welter of meaning and acquired a thick lacquer of myth that may never now be removed, despite the best efforts of researchers such as Andy Roberts. As with events reported from Rendlesham Forest, the words "Berwyn Mountain UFO" are rarely uttered without the phrase "Britain's Roswell" appearing somewhere in the vicinity. The original events - puzzling as they remain - have been subsumed into folkloric motifs such as retrieved flying saucers, extra-terrestrial bodies, 'men in black' and official cover up.
As such, it is a beguiling case for the student of folklore to study - in that the actual events themselves are comparatively well documented, as is their subsequent expansion into living legend.
See also: folklore