The Hoover Dam (known formerly as Boulder Dam), has been one of the U.S.’s most popular tourist attractions since its opening in 1936. The massive structure is 726 feet high and 45 feet thick, and is filled with enough concrete to pave a 16-foot-wide by eight-inch-thick strip from San Francisco to New York City. The dam can allow over 100-million gallons of water to pass through its walls each year, and the behemoth structure is absolutely awe-inspiring. The tours of the dam are very educational and contain enough material to interest even the youngest members of the family. Tours are available to the public and are lead by friendly and incredibly knowledgable guides from the U.S. Bureau of Reclamation. The Powerplant Tour lasts 30 minutes and includes plenty of exhibits — including film and audio presentations — to help visitors better understand the tremendous structure and its operations. it even includes a tour of the Nevada powerplant balcony, where tourists view and learn about eight of the dam’s 17 massive hydroelectric generators. The hour-long tour includes a full guided tour of the plant, the passageways of the dam itself and admission to the Visitor Center.