We visited the oldest Spanish style building in Arizona the CatholicMission San Xavier, started 1783 and opened as church in 1797.
There was a bunch of scaffolding in the church as they are always working on restoring the paintings and statues. When we got home I found I not taken any overall pictures of the inside of the church ( ripped these from the church website ).
These are some of the original beams that were then covered with saguaro cactus internal wood ribs and then adobe.