Frank Lloyd Wright was an American architect known for promoting organic architecture that was in harmony with humanity and the environment. Some of his most famous works include Fallingwater, which was built directly over a waterfall in Pennsylvania. Fallingwater used reinforced concrete, steel, glass and sandstone to appear as if it was part of the natural surroundings. It became renowned for being built in harmony with nature rather than just overlooking it. Wright designed the house to have the waterfall incorporated into the occupants' daily lives rather than just being something they looked at occasionally. Fallingwater demonstrated Wright's mastery of using basic shapes and modern construction techniques to create structures that blended seamlessly with their natural settings.