Frank Lloyd Wright was one of the most influential architects of the 20th century known for his Prairie Style homes and sculptural Guggenheim Museum. His Fallingwater house, built in 1935 over a waterfall in Pennsylvania, mimics natural stone ledges and is constructed of local sandstone, with cantilevered concrete trays forming living spaces dramatically over the stream. Additional works include the Guggenheim Museum in 1959 and Roby House in 1906, and Wright often designed internal furnishings as well.