Fallingwater
A private residence built for department store magnate Edgar Kaufmann Sr. over a waterfall on Bear Run in the mill run of the Allegheny Mountains, consisting of a series of reinforced concrete trays — cantilevering dramatically over the stream at each level — that appear to hover above the waterfall without touching it. The materials — local sandstone, reinforced concrete, and glass — were chosen to integrate the building into its site, and large boulders from the forest floor appear as features of the interior. Wright designed the house in two hours, reportedly having done nothing during the three months Kaufmann's son was driving from Milwaukee to Wisconsin to see the drawings.
Fallingwater is the most famous private house in American architecture and the building most completely expressing Wright's philosophy of organic architecture — the idea that a building should grow from its site rather than being imposed upon it. It was named the "greatest work of American architecture of all time" by the American Institute of Architects in 1991. Its structural audacity — the cantilevered concrete trays have deflected significantly beyond engineering tolerances — remains both its most celebrated and most problematic feature.
Wright designed Fallingwater in 1935 during a period of creative resurgence following years of personal and professional difficulty. Its 1938 publication in Architectural Forum reestablished Wright as the most important American architect at a moment when European modernism — in the form of Mies, Gropius, and Breuer, arriving as refugees from Nazi Germany — was threatening to make his Prairie Style seem dated.