Americans didn't let mountains stand in the way of trade with the American West--they tunneled right through them to make the Cascade Tunnel and Hoosac Tunnel. When water and power were needed, they built huge dams, such as the Fort Peck Dam and the Hoover Dam. Faced with water to cross, they built beautiful bridges, such as the Brooklyn Bridge and the Chesapeake Bay Bridge-Tunnel. And the American character is best reflected by the building it invented, the skyscraper. Built to last profiles 17 architectural and engineering marvels, from the Erie Canal to Boston's Big Dig.