In a special celebration of the proud history of coal mining in Wales, Lucy Owen and Will Millard explore above and below ground at the Big Pit museum in Blaenavon. A quarter of a million miners once worked in more than 3,000 Welsh collieries, risking their lives to power homes and industry. Now, ten years on from the closure of the last deep mine in Wales, Tower Colliery, the workers are reunited to celebrate their incredible achievements and reflect on their memories of life underground.