The Grande Dixence Dam () is a concrete gravity dam on the Dixence at the head of the Val d'Hérémence in the canton of Valais in Switzerland. At high, it is the tallest gravity dam in the world, sixth tallest dam overall, and the tallest dam in Europe. It is part of the Cleuson-Dixence Complex. With the primary purpose of hydroelectric power generation, the dam fuels four power stations, totaling the installed capacity to , generating approximately annually, enough to power 400,000 Swiss households. The dam withholds the Lac des Dix (meaning: "Lake of the Ten"), its reservoir. With a surface area of 4 km2, it is the second largest lake in Valais and the largest lake above 2,000 m in the Alps. The reservoir receives its water from four different pumping stations; the Z’Mutt, Stafel, Ferpècle and Arolla. At peak capacity, it contains approximately of water, with depths reaching up to . Construction on the dam began in 1950 and was completed in 1961, before officially commissioning in 1965. History In 1922, Energie Ouest Suisse (EOS) became established with a few small power stations. To generate substantial amounts of electricity, EOS looked to the Valais canton which contains 56% of Switzerland's glaciers and stores the largest amount of water in Europe. In 1927, EOS acquired the license for the upper Dixence basin. In 1929, 1,200 workers constructed the first Dixence dam which would be complete in 1935. The first dam would supply water to the Chandoline Power Station which has a capacity of 120 MW. After the Second World War, growing industries needed electricity and construction on the Cleuson Dam began in 1947 and was completed in 1951. The original Dixence dam was submerged by the filling of Lac des Dix beginning in 1957, it can still be seen when the reservoir level is low. Plans for the Super Dixence Dam were finalized by the recently founded company, Grande Dixence SA. Construction on the Super Dixence Dam began in late 1950. By 1961, 3,000 workers had finished pouring of concrete, completing the dam. At 285 m, it was the world's tallest dam at the time, but it was surpassed by the Nurek Dam of Tajikistan in 1972 (300 m). It remains the world's tallest gravity dam. In the 1980s, Grande Dixence SA and EOS began the Cleuson-Dixence project which improved the quality of electricity produced by building new tunnels