Slate mines: Hidden world's beauty revealed by explorer

The hidden world of forgotten slate mines in north Wales has been revealed by a photographer who has spent five years exploring them.

Gareth Owen, 32, has been documenting the huge caverns and clusters of perfectly preserved boots, lanterns and tools during subterranean trips with other highly-trained cavers.

The photographs and videos he captures give a peek into a world frozen in history, deep underground – and often only accessible by tiny, dangerous passageways.

"As soon as you go in through that adit, you could literally be back in the 1800s," he said. "It's like going back in time."