We "happened" upon Montezuma in Arizona on one of our first trips there. We were staying two weeks in Sedona and took many exploring day trips. This was our first introduction to these tribes. They were the Sinaquas, an ancient Indian tribe who built the cliff dwellings about 700 years ago in the early 1300s. For unknown reasons, the Sinaqua abandoned their homes in this Verde Valley Arizona area in the 1400s. Perhaps they had over extended agricultural pressure on the land. Or perhaps there was a lengthy drought or they could have been eliminated through conflict with the Yavapai Indians that still exist today. If there were any Sinaqua survivors, they were likely absorbed into other Indian tribes to the north.
It is considered to be one of the most preserved ancient cliff dwellings in America.
What astonishes me is that we were completely unaware of this monumental dwelling! However, since then, we have discovered many more of these wondrous sights.