Summary On the evening of 23 January 1974, the quiet Welsh village of Llandrillo was rocked by a loud explosion and impact. The police were inundated with 999 calls, and it was at first assumed that a plane had crashed on the nearby Berwyn Mountains. Witnesses came forward and described a bright, spherical object arcing across the sky. A local nurse gave her account of seeing a large glowing ball of light on the mountainside. The military became involved, and rumours began to circulate that this was a UFO, not a plane. At the same time, geologists theorised that this was an earth tremor - the impact had been measured at 3.5 on the Richter scale, and bright flashes of light often accompany these events. Sadly, no tangible evidence has been produced, and so the case remains a mystery to this day.

• Documentary