Wales has many waterfalls, including some of the most striking in the United Kingdom. One such is the Pistyll Rhaeadr near the village of Llanrhaeadr-ym-Mochnant. It is formed as a mountain stream drops over a cliff and changes character to a lowland river, the Afon Rhaeadr. The site was designated by the Countryside Council for Wales as the 1000th Site of Special Scientific Interest in Wales, because of its importance to an understanding of Welsh geomorphology. The 19th-century English author George Borrow remarked of the waterfall, "I never saw water falling so gracefully, so much like thin, beautiful threads, as here."