Good question.
We have several completely empty (like everyone left, leaving their goods in place) indigenous villages in the desert SW. One on our ranch in NM you can only access by a narrow gorge and then built into a cave system. Spring fed water flowing out from the mountains.
It’s on private land and we’ve kept it fairly quiet to avoid looters.
The university people we’ve let see it think it was plaque or more likely hanta virus which ripped through North America in the late 1400/1500s. Greatly depopulated the Americas just in time for Europeans to come in force.
Plague! Stupid quick correct.