Just outside of Tucson, Arizona is the old Spanish Mission of San Xavier del Bac. The building in this photo was built between 1783 and 1797. It is widely considered to be the finest example of Spanish Colonial architecture in the United States. I have visited this site quite a few times and it is always impressive. It is a functioning mission of the Catholic Church dating back to Father Eusebio Francisco Kino in 1692. It is open to the public except when being used for church services.