Fallingwater, a private residence improbably suspended over a waterfall, is about a two-hour drive northwest from Pittsburg, Pennsylvania, halfway between the villages of Mill Run and Ohiopyle on PA Route 381. It is a masterwork of Frank Lloyd Wright, one of America's most important architects. The history of Fallingwater began in 1936, when Pittsburgh department store owner Edgar J. Kaufmann hired Wright to design a weekend retreat for his family, on land in Mill Run. Incorporating much of what was already on the site, including rocks, trees, and a rushing creek, the house was set amid 5,000 acres of natural wilderness that juts out over a waterfall on Bear Run. The building was constructed of sandstone, reinforced concrete, steel and glass, and built by local craftsmen. The stone serves to separate reinforced concrete trays, forming living and bedroom levels dramatically cantilevered over the waterfall. The house extends 30 feet in height above the rock ledges, although strong horizontal lines and low ceilings help to maintain an overall sheltered feeling. The guest and service wing were completed in 1939. The unique attraction of the house is the waterfall over which it is built. Fallingwater remained the weekend home of the Kaufmann family from 1937 to 1963, when the house, its contents and grounds were donated to the Western Pennsylvania Conservancy by Edgar Kaufmann Jr. Fallingwater is the sole remaining Wright house with its setting, original furnishings, and artwork intact. The masterpiece was opened to the public in 1964. The visitors pavilion contains the exhibits on Fallingwater, a child care center, a café, an interpretive nature trail, and a museum shop featuring postcards, film, books, Fallingwater furniture reproductions, and gift items. Guided tours are scheduled regularly. Designated a National Historic Landmark, Fallingwater also was named by the American Institute of Architects in 2000 as the "Building of the Century."