Pittsburgh, Penn.

Frank Lloyd Wright's Fallingwater (above), Kentuck Knob and Duncan House can all be seen in a daytrip from Pittsburgh. The famously zen Fallingwater, which inspired Ayn Rand's classic novel The Fountainhead and recently underwent a $5 million restoration, is a cantilevered structure that sits partially atop a stone waterfall in the middle of the woods. The water passes underneath, which helps the structure blend with its natural surroundings. It was voted "the best all-time work of American architecture" in 1991 by the members of the American Institute of Architects.