The southwest has plenty of layers on layers. Tucson is built on a Spanish fort, which is built on native villages on top of yet older native villages going back almost 4,000 years, as one example.

For another example, most neighborhoods in eastern phoenix are built on top of old Hohokam villages, adjoining older basketmaker sites. The canals throughout the city often follow the old Hohokam canals. Fun fact, the Intel Chandler campus is on top of old hohokam suburbs of Pueblo de los muertos, which is buried under the modern suburbs.