In the early 19th century mountain climbers began to come to Guttannen to explore the high peaks above the valley. In 1811-12 the Finstaarhorn was climbed and by the 1830s Louis Agassiz had popularized mountain climbing and trained guides in Guttanen. The Grimsel Pass road (built 1894-95) further opened up the village to trade and tourism. The construction of five hydroelectric dams and six reservoirs in the Grimsel Pass, between 1925 and 1975, brought prosperity to the village. The Kraftwerke Oberhasli (KWO) company was founded in 1925 to manage the power plants and today is the largest employer in Guttannen. A modern road was built over the pass over a 26-year period (1960-1986).