Berwyn Mountain UFO incident
On 23 January 1974 on the Berwyn Mountains in Llandrillo, Merionethshire, North Wales, lights and noises were observed that were alleged to be related to a UFO sighting on Cadair Berwyn and Cadair Bronwen. Scientific evidence indicates that the event was generated by an earthquake combined with sightings of a bright meteor widely observed over Wales and Northern England at the time.
On the evening of January 23, 1974, residents of the Berwyn Mountains area in North Wales reported a loud noise and a bright light in the sky. When UFOlogists claimed that a UFO crashed and the British Government covered up the military's recovery of a crashed spaceship, some tabloid newspapers jokingly labelled it "The Roswelsh Incident". 
Declassified Ministry of Defence documents suggest the incident was caused by the combined effects of an earthquake and a meteor. The Institute of Geological Sciences (now British Geological Survey) reported that a magnitude 3.5 earthquake was felt at 8:38 p.m. that night over a wide area of North Wales and as far as Liverpool (also in Formby 13 miles north of Liverpool). It was not immediately identified for what it was, hence the police investigation. However, the magnitude of the shock was such that had it been due to impact, the resulting crater would have been large enough to be easily visible. The unusual lights reported may have been simply the meteor, but may also have included the phenomenon known as earthquake light.
- Musson, R.M.W., 2006. The enigmatic Bala earthquake of 1974. Astronomy & Geophysics, vol 47 no 5, pp 11–15
- McBeath, A., 2006. Meteor, not shower, over Bala. Astronomy & Geophysics, vol 47 no 6, p 8
- Devine, Darren (August 5, 2010). "Released files cast light on famous Welsh ‘UFO’ sighting". Wales Oline. Retrieved 10 March 2015.
- The Sun (2011-01-31). "The Roswelsh Incident". London. Retrieved 2011-01-31.