Aiguestortes i Estany de Sant Maurici

Declared in 1955, it is the only national park in Catalonia and in the whole of the Catalan Pyrenees. Its name — "twisted waters" — describes the landscape quite literally: a network of more than 200 glacial lakes (estanys) linked by winding rivers in a valley shaped by successive Quaternary ice ages. Before it was protected, the area was heavily developed for hydroelectric power in the early 20th century, which altered the regime of several of its lakes — scars still visible today, and which shaped the debate in Spain over how far industry should go in natural areas.