Wupatki National Monument
More information is available here and here.
Just a few miles north of Sunset Crater Volcano near Flagstaff is Wupatki National Monument. Both sites are located about fifteen miles north of Flagstaff along a scenic loop that covers about 50 miles off US 89 beginning at Sunset Crater, then meanders along Route 395 back to 89 about 15 miles north of the Sunset Crater Visitor Center. After our visit to Sunset Crater on our first day in Flagstaff, we decided to go back another day and spend some time at Wupatki. We did not try to cover the entire Wupatki site complex. A number of the 2500 documented sites of the complex are accessible by trails and we had a bit of a time trying to decide which to explore. We were trying to get to Sedona, AZ later in the day, so our ramblings took us to the Lomaki (Hopi for "Beautiful House") site where we walked among many abandoned structures of these ancient people.
More photos of some of the ruins