Hoover Dam, Colorado River, Arizona, Nevada

Hoover Dam, once known as Boulder Dam, is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the US states of Arizona and Nevada. It was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President Franklin D. Roosevelt. Its construction was the result of a massive effort involving thousands of workers, and cost over one hundred lives. The dam was controversially named after President Herbert Hoover.

Hoover Dam takes shape from the concrete columns in which it was poured (shot from cableway control tower downstream on Nevada rim, so looking upstream) | Bureau of Reclamation photographer

 Photograph of the Hoover Dam (formerly Boulder Dam) from Across the Colorado River;
From the series Ansel Adams Photographs of National Parks and Monuments, compiled 1941 - 1942, documenting the period ca. 1933 - 1942.

                                    The Hoover Dam Bypass,  Photo by Keith Philpott, courtesy of HDR

 The Hoover Dam Bypass is being described as a remarkable, magnificent, impressive, spectacular, and monumental engineering feat. Completed in October 2010, this $240 million civil engineering project took nearly a decade of intensive planning and preparation, required coordinated efforts among a six-agency management consortium, and consisted of a three-prong emphasis on design, safety, and economic considerations.