There in a beautiful forest was a solid, high rock-ledge rising beside a waterfall, and the natural thing seemed to be to cantilever the house from the rock-bank over the falling water...I think you can hear the waterfall when you look at the design. -Frank Lloyd Wright. Frank Lloyd Wright's architectural masterpiece is one of the best known houses in the world. Designed in 1935, Fallingwater is intimately related to the rock ledges, trees, and waterfall of the western Pennsylvania landscape which Pittsburgh's Kaufmann family used as a weekend retreat. More than 3 million people have visited Fallingwater since it opened for public tours in 1964. All tours are guided led by professional interpreters. Kentuck Knob, situated just below the crest of a hill, appears almost part of the mountain...