The Main Quadrangle, or more commonly Main Quad or simply Quad, is the heart and oldest part of Stanford University in California. The collection of connected buildings was started in 1887 and completed in 1906. The Quad was damaged in the 1906 earthquake, repaired, less severely damaged in an 1989 earthquake, and repaired again. The exteriors have remained almost the same since the beginning, though the interiors of most of the buildings have changed radically. The Main Quad is still used for its original purposes of teaching, research, and administration.