In 1935, Paul and Jean Hanna commissioned Frank Lloyd Wright to design their home to be built on the Stanford University campus. Construction, begun in 1937, continued in four stages over 25 years. The house was the first structure in the world to use Frank Lloyd Wright's hexagonal grid system, which has subsequently been used widely in American architecture. The Hannas lived in the house until giving it to Stanford in 1975. It housed four university provosts until suffering severe damage in the 1989 Loma Prieta earthquake. It underwent complex restoration, made complicated by its unique design, and reopened to the public in 1999.