Horseshoe Falls - a weir on the River Dee near Llantysilio Hall in Denbighshire, Wales, about 5 kilometres (3 mi) north-west of the town of Llangollen. The distinctively shaped weir, which is 460 feet (140 m) long, helps create a pool of water that can enter the Llangollen Canal (via an adjacent valve house and flow meter). Wikipedia.