DOLGARROG (AFP): A surf park on the edge of Snowdonia National Park in Wales opens Saturday, a 300-metre (985-foot) long lagoon that promises the longest man-made surfable waves in the world. The £12 million ($18.7 million, 17-million-euro) project will see barrelling waves crash back and forth across the lagoon, offering a 20 second ride. The waves are created once a minute by a plough-like weight that moves underwater along a central pier, using technology from Spanish company Wavegarden. Wavegarden has a prototype surf centre near San Sebastian in northern Spain but Surf Snowdonia, built on a former aluminium works, is the first to be open to the public.