Montezuma Castle National Monument

Montezuma Castle National Monument protects a set of well-preserved dwellings located in Camp Verde, Arizona which was built and used by the Sinagua people, a pre-Columbian culture closely related to the Hohokam and other indigenous peoples of the southwestern United States, between approximately 1100 and 1425 AD. The main structure comprises five stories and twenty rooms and was built over the course of three centuries. This is probably an "opportunity" stop rather than a destination. The resource that's available to you is small (a 1/3 mile loop trail that takes you to various vantage points from which you can view the cliff). There are other NPS facilities nearby (Waputki, Walnut Canyon) that are similar, albeit from different historical periods/peoples. If, however, you decide to make the stop, it's a fairly typical NPS site - you're not likely to find a park ranger (but you'll find a fee collector at the desk). Parking is free, but there's a $10 entry fee.