Rated by the American Society of Civil Engineers as one of America's Seven Modern Civil Engineering Wonders, the Hoover Dam was commissioned in 1932 by Herbert Hoover to counter the flooding problems caused by the Colorado River. Requiring almost five years and several thousand workers to build, the 726-foot-high dam is an amazing example of complex design, architecture and construction. The structure produces 2,080 megawatts of electricity and its creation necessitated the formation of Lake Mead, the largest man-made lake in the United States, which is popular for boating, fishing and swimming. Located 30 miles southeast of Las Vegas on the Colorado River's Black Canyon along the Nevada-Arizona border, daily tours of the dam start at the newly constructed visitor center. « less