The Flintstone House is a free-form, single-family residence in Hillsborough, California overlooking, and best seen from the Eugene A. Doran Memorial Bridge on Interstate 280. It was designed by architect William Nicholson and built in 1976 as an experiment in new building materials, in the form of a series of domes. It was constructed by spraying shotcrete onto steel rebar and wire mesh frames over inflated balloons. Originally off-white in color, it was repainted a deep orange in the early 2000s.