Filling in from my recent road trip - no need to comment.
This shows the outside and inside of an Hohokam "pit house," built in the Sonoran desert. Houses of this type were built from at least 4,000 years ago up until about 1400.
The door to the outside can be seen on the left side of the lower picture.
10/1/2020: Finished year 7 (!), with continuing gratitude towards this amazing community. Based in St. Louis, MO. Regular worker-bee and self-taught photography dilettante....
It's interesting to see how the walls are lined with bark or grasses or reeds. I wonder if they provide additional insulation for the thick adobe walls.
@randystreat I learned that the walls are lined with the inside structures of the saguaro cactus. That is an excellent question, though! The reeds are formed by the vertical woody spines of the cactus, which are available after the cactus falls or is cut down. Apparently, they are quite strong and light.