San Xavier del Bac Mission
San Xavier del Bac was founded as a Catholic mission in 1692 but construction on this church did not start until 1783 and wasn't completed until 1797. One of the bell towers was never finished, but San Xavier is the oldest European structure in Arizona.
The White Dove of the Desert, as it is known, was part of New Spain when it was built. It became part of Mexico in 1821 with Mexican independence and then part of the United States after the Gadsden Purchase in 1854.
San Xavier, about nine miles southwest of downtown Tucson, is on the Tohono O'odham Nation. About 200,000 people visit the mission annually. It is currently undergoing restoration work on the east tower.