I visited the Mission San Xavier del Bac near Tucson in 2012 as part of an escorted coach trip. It was a very interesting building & well worth a visit if you are in the Tucson, Arizona area.
Mission San Xavier del Bac is a historic Spanish Catholic mission located about 10 miles south of downtown Tucson, Arizona, on the Tohono O'odham San Xavier Indian Reservation. It was founded in 1692 by Padre Eusebio Kino & named for a pioneering Christian missionary and co founder of the Society of Jesus, Francis Xavier. In 1700 construction began on a church at a site nearby the current Mission. It served the community until razed by Apaches in 1770.
Today's Mission was built between 1783 & 1797 and is the oldest European structure in Arizona. Widely considered to be the finest example of Spanish Colonial architecture in the United States, it hosts some 200,000 visitors each year.
The site is also known as the 'place where the water appears', as there were once natural springs in the area. The Santa Cruz River, which now runs only part of the year, is also nearby. The Mission is situated in the center of a centuries old Indian settlement of the Tohono O’odham (formerly known as Papago), located along the banks of the Santa Cruz River.