While the more famous Hoover Dam (conveniently located between Las Vegas and the Grand Canyon) gets over a million visitors per year, the much larger (four times) and arguably more significant Grand Coulee Dam (inconveniently located far from everything) gets only a trickle of tourism. It's the largest concrete structure in the US and also the largest producer of electricity in the US.
The Grand Coulee Visitor Arrival Center details the history of the dam and surrounding area with movies, photos and interactive exhibits, while free guided tours of the facility run on the hour from 10am to 5pm (from May to September); there fewer tours outside summer.
Similarly spectacular is the nightly laser show – purportedly the world's largest – which illustrates the history of the Columbia River and its various dams against a gloriously vivid backdrop.
