Fallingwater (1935, Mill Run, Pennsylvania)

Fallingwater is among the world’s best-known private residences. An astonishing construction and a consummate example of the union of architecture and nature, the house was designed as a series of three horizontal trays (floors), stacked one upon the other that appear to soar with no support, outward over a 30-foot waterfall below. Fallingwater masterfully integrates reinforced concrete, steel, and glass—along with the natural materials of wood and native stone—to create a unique building whose daring cantilevered construction stretched the limits of design and technology of the period. Fallingwater is also an astonishing expression of its physical site: the house cascades down the hillside like the water over the rocks below. Today the house is a museum operated by the Western Pennsylvania Conservancy.