Taken at Casa Grande National Monument. The ancient building is now under a protective cover. The ranger is describing the structure and its history. The walls are made of adobe from the topsoil of the desert. It must have taken quite a large group of people to excavate, form the adobe "bricks" and then erect the walls of this structure.

See PiP for more.

If you are in Arizona, be sure to visit the National Monument.

www.nps.gov/cagr/index.htm

Image processed with GIMP.