The Hohokom people.
This was the first archaeological site in America to be protected by the United States government. Casa Grande Ruins is located near the towns of Coolidge and Casa Grande. Designated an "archaeological reserve'' in 1892 and a national monument in 1918, the centerpiece of Casa Grande is a 4-story structure.
The Casa Grande monument was built about 700 years ago around AD1300-1350 by the Hohokam natives. Before this they lived in pit houses.
The ruin, often referred to as the "Great House'' or "Big House'', sits on flat terrain and is now protected by a metal canopy that deflects the bright sun and heat of this portion of Arizona, where temperatures often reach 80 degrees during the winter and 110 in the summer.
The purpose of the building itself is a mystery, though some believe it may have been an astrological observatory due to the way the building is positioned and aligned with the moon and sun. It measures about 60 feet by 40 feet and had walls that were more than a meter thick.
Wooden beams support the meter thick walls. The exterior was fashioned from a material known as caliche, which is a naturally-occurring soil made of clay, sand, and calcium carbonate, typically found in the deserts of the American Southwest.
The park guide said that the ground here is so hard that one needs either a pick, a jack hammer or dynamite to get through the surface. And that is the reason how this 4 story dirt and mud combination stood.
These natives were the first to use irrigation through the use of canals and dykes. They planted corn, and then planted beans around the corn to provide nitrates for the corn, and then squash around the beans to provide shade for the roots of both the corn and beans. Very smart!!
The Hohokom abandoned the complex around the 16th century for reasons unknown. They are now scattered around the area and are not extinct.