On September 30, 1935, Hoover Dam, one of the great engineering feats of the twentieth century, was formally dedicated during a ceremony attended by President Franklin D. Roosevelt. Authorized under the Hoover Administration and built in one of America's most inhospitable settings, thousands of workers and their families came to the Nevada desert to help tame the mighty Colorado River. Despite unprecedented engineering challenges and summer temperatures in excess of 120 degrees, Hoover Dam was completed ahead of schedule in only three years. Rising 726 feet above the raging waters of the Colorado River, the dam ended the Imperial Valley's endless cycles of flood and drought and provided renewable energy for the growing Southwest. The dam, constructed in the midst of the Depression, also renewed national faith in American ingenuity and technology. Officially designated "Boulder Dam" by the Roosevelt administration, its original name-Hoover Dam, after Roosevelt's predecessor in the White House-was restored in 1947.