Since Euro-Americans settled near Spokane Falls in the 1870s, the riverfront has served many purposes shaped by changing values and technologies, functioning as a source of energy, a transportation and industrial center, and later a scenic residential and recreational resource. In the 1870s and 1880s, water power drove sawmills and flour mills along the riverbanks, while Samuel Havermale and James Glover acquired much of what is now Riverfront Park. As industrialization advanced, rail yards and depots turned Havermale Island and the area that became Spokane Falls Boulevard into a transportation hub, especially after the Northern Pacific Railway arrived in 1881, and the island's clock tower began as part of the Great Northern Railroad's Spokane depot. To meet early regional demand for electricity, hydroelectric facilities were built at Spokane Falls, including the Diversion Dam, constructed in 1922 as part of Avista's Upper Falls Hydroelectric Development, which regulates water flow through the south channel of the Spokane River into the Upper Falls Intake and Powerhouse. Despite its industrial character, by the 1960s people increasingly saw the riverfront as a place for recreation and entertainment, and urban renewal in downtown Spokane made a revitalized riverfront central to that effort. Railroad tracks were removed, new structures were built for the 1974 World's Fair, which drew more than five million visitors, and in 1978 President Jimmy Carter formally dedicated the fairgrounds as Riverfront Park.