Kentuck Knob

What does one do when Frank Lloyd Wright builds one of the most famous houses in the world for your friends? Ask him for one, of course.

Only seven miles away from Fallingwater, Kentuck Knob was built for the Hagan family, owners of a large dairy and friends of the owners of Fallingwater, the Kaufmans. Then 86, Wright said that he "could shake it out of his sleeve at will" and designed the house in his signature Usonian style around a still-fully-functioning hexagonal kitchen. The 240 degree L-plan home is made with opulent natural materials such as native sandstone, red cypress, and a $96,000 copper roof.

The Hagans lived at the house for 30 years before selling it in 1986 to Lord Peter Palumbo. Lord and Lady Palumbo entertain guests here on occasion, and they have also set up a public tour program similar to estates in the UK. They have also added art installations and a sculpture garden to the grounds that include a slab of the Berlin Wall.

One of his last designs, Wright actually only set foot on the property once, for a brief visit during construction.