Remembering the Aberfan disaster

It's fifty years to the day since a great mountain of waste slid onto the village of Aberfan and crushed the primary school. Fifty years and the world still remembers. Not just because of what happened - so many children buried alive - but because of why it happened.

John Humphrys has been back to the Welsh village of Aberfan to speak to those who remember.

(Image: people searching through rubble, credit: AP)