Just outside tiny Mill Run, Pennsylvania (about two hours from Pittsburgh), is the most celebrated house of the twentieth century. Fallingwater -- the weekend home built by Frank Lloyd Wright for Pittsburgh tycoon Edgar Kaufmann in 1935 -- has been open to the public since 1963. Yet it still seems less museum than private home, and the extended tour, which shows back rooms as well as the usual spaces, makes it seem doubly so. Tour guides are stuffed full of facts about Wright's genius, his quirks, his leaky roofs: The architect famously told one irate client, who called to complain that water was dripping into his dinner party, "Move your chair." Needless to say, you can't stay at the house, which is in a nature preserve, so eat and sleep at the nearby River's Edge Cafe and B&B.
Details Fallingwater, 724-329-8501 (open March through mid-November, plus Christmas week and December weekends; tour reservations required; admission $10 weekdays, $15 weekends; in-depth tour, $40 weekdays, $50 weekends); Rivers Edge Cafe and B&B, 814-395-5059 (doubles are $60).