Paddle rolling a kayak - from underwterRiver Dart, UKCwmorthin Slate Mine, north Wales, UKRabbit Mine, Godstone, UKRabbit Mine, Godstone, UKCaver in Victorian borehole. Abercwmeiddaw slate mineCae Coch Sulphur MineOgof Ffynnon Ddu cave, South Wales, UKDroitwich Lido, UKRed Sea