There is an amazing walk from a Forestry Commission car park near Ystradfellte in Powys, South Wales, https://www.ramblers.org.uk/ystradfellte-powys-free-route. Its quite strenuous, with exposure and large drop offs, but it is truly wonderful walk with spectacular scenery. There are lots of opportunities for bathing on route and even a chance of some enthralling activities. At the final waterfall there is a chance to go behind the curtain of water.
Nature and Travel Photography in 3D 