Hoover Dam does its job well.


From the moment you first see it, you have no doubt that this massive sheet of gray concrete can keep the mighty Colorado River tamed forever.


The dam was conceived in the 1920s as a way to finally control the Colorado River, which habitually flooded much of the fertile farmland in Southern California. Work began in 1931 and the structure was completed in 1935 — two years ahead of schedule. Hoover Dam may have been one of the few times that hyperbole matched reality. It has been called one of the seven architectural wonders of the world and lives up to its billing.


This is one huge dam. While a handful of newer dams may be larger — Hoover is now the third highest in the world — it’s important to remember that this dam was built more than 50 years ago during America’s Great Depression.


Despite its age, statistics about the dam remain staggering. It contains 4.4 million cubic yards of concrete, enough to pave a two-lane highway from San Francisco to New York. It is 726.4 feet high and 1,444 feet across Black Canyon.


The waters of the Colorado that are held back by the dam form Lake Mead, the world’s largest man-made reservoir with a capacity of more than 28 million acre-feet. (An acre-foot is about 326,000 gallons.)


While it appears to be a giant curved curtain, the dam is actually a huge upside-down wedge, with a base in the bedrock that is 660 feet thick. It’s difficult not to be impressed, standing at the top and looking 528 feet straight down to the Colorado River.

Engineers point out that Hoover Dam was “overbuilt,” meaning it contains far more concrete and metal support than is actually necessary to do its job. It was built to last — perhaps for centuries.


Tours of the dam are given every few minutes and more than 32 million people have toured the dam since it opened in 1935. The tour begins at the top and within minutes an elevator drops the full 520 feet to the base.


Inside the dam there are small architectural touches typical of the 1930s. Art Deco and Streamline Moderne designs, all the rage in the 1930s, are incorporated into the structure. There are also stylized Native American designs in the floor tiles.


At the base, visitors tour a massive chamber filled with 17 hydroelectric generators that supply about 3.5 billion kilowatt-hours of energy a year. From there, the tour goes deep inside the dam to see the huge diversion tunnels built to divert the river around the dam during construction.


Back at the top, on the Nevada side (the dam spans the Nevada-Arizona border), the Visitors Center displays describe the entire Colorado River water system — how it starts and where it ends — and the history of the dam.


The exhibit gallery, opened in April 1997, uses photos, artifacts, artwork, and audiovisuals to tell the story of the dam, the builders, what happens during a desert thunderstorm, and the southwestern environment, geology, plants, and animals. There’s a parking structure, gift shop, and food concession.


Hoover Dam is located 30 miles southeast of Las Vegas on U.S. Highway 93. Tours are offered daily starting at 9 a.m. with the last tickets sold at 5:15 p.m. The tour center closes at 6 p.m. The cost is $11 for adults, $9 for seniors and military, $6 for juniors and free for children 6 and under. Parking is $7, cash only. For more information contact the Bureau of Reclamation, (702) 293-1081. Visit the dam’s web site at http://www.usbr.gov/lc/hooverdam/.