A collapsing coal-waste tip buried a Welsh school, killing 116 children

On 21 October 1966, a rain-soaked colliery spoil tip above Aberfan, Wales, liquefied and slid downhill as a wall of slurry, engulfing Pantglas Junior School. The disaster killed 144 people, 116 of them children. A tribunal later found the National Coal Board had ignored years of warnings that the tip was unstable and sitting over a natural spring.

— Standard historical accounts, Aberfan disaster — 21 October 1966; Aberfan Disaster Tribunal report