Roll On, Columbia, Roll On near Cascades Rapids, in The Dalles, and on Memaloose Isle. The final three verses describe the construction of two Columbia River dams: Bonneville Dam and Grand Coulee Dam. Bonneville Dam, the first dam built on the Columbia, had locks built into it so ships could navigate past it, alleviating worries that a dam would prevent the shipment of goods and passengers along the length of the river. Guthrie's lyrics describe Grand Coulee Dam as "the mightiest thing ever built by a man"; when it was built it was the largest concrete dam in the world, and as of 2012 it
Grand Coulee Dam the reservoir is reserved for tribal hunting and boating. Built in the late 1970s, the Visitor Center contains many historical photos, geological samples, turbine and dam models, and a theater. The building was designed by Marcel Breuer, and resembles a generator rotor. Since , on summer evenings, the laser light show at Grand Coulee Dam is projected onto the dam's wall. The show includes full-size images of battleships and the Statue of Liberty, as well as some environmental comments. Tours of the Third Powerplant are available to the public and last about an hour. Visitors take a shuttle to view