LEGO Architecture: Fallingwater
Frank Lloyd Wright's Fallingwater house, located in Mill Run, Pennsylvania, is another popular tourist destination due to its position extending out over a waterfall and stream. The model is only 1'4" tall, but it consists of 21,100 pieces. It took 170 hours to design and 130 hours to build.
Photo of LEGO Architecture exhibit by Wally Bahny for TechRepublic
I believe the open areas are actually parking. Odd, but there's parking spaces with cars in them all around the outside of the building. Not sure how they get up there, I always assumed some sort of elevator.