Gaddings Dam is often described as England's highest beach, a reservoir at around 1,300 feet that has developed a sandy shore on its south side and become popular for wild swimming in summer. The walk up from Todmorden takes about an hour through heather moorland; the climb is real and the reward, on a warm day, is a mountain lake experience that feels improbable for West Yorkshire.
Swimming is permitted and the community association has made the site welcoming, but be aware that the water is cold year-round and there are no lifeguards. The surrounding moorland is excellent for walking, and the views back down into the Calder Valley on a clear day are worth the ascent even if you do not swim.