The Grotte Casteret, also known by its Spanish name Gruta Helada de Casteret, is a limestoneice cave, located high in the SpanishPyrenees, within the Ordesa y Monte Perdido National Park. Discovered in 1926 by Norbert Casteret, it is known for its Grande Salle (Great Hall) which has a frozen lake some 2,000 square metres (22,000 sq ft) in area, its ice formations, and a 20 metres (66 ft) ice wall into a second chamber.