We have been exploring the area around Casa Grande starting with the Casa Grande Ruins National Monument east of town. This "Great House" is the largest known structure built by the ancient natives of the Sonoran Desert. The 4 walls face the compass points, there is a hole in the upper wall that aligns with the setting sun at the summer solstice and other holes that align with the sun and moon at specific times. Our own North American Stonehenge! In order to preserve the clay walls from further decay, a protective roof was built over it. This great house was near the center of a walled village and there is no explanation for it's abandonment.
Then we drove through mountains and desert to the northeast to Tonto National Monument near Roosevelt Lake on the Salt River. Tonto contains several cliff dwelling sites, we visited the Lower Cliff Dwelling which was only a one mile hike/climb. The Salado People built these dwellings over 700 years ago. Earlier they had farmed the Salt River Valley. It has been determined that flooding occurred in this valley followed by severe drought in the 1300s. The current theory is that the Salado People headed to the hills at that point. By 1450 they gave up this way of life and migrated to many locations becoming some of the current tribes of the area.