Cliff dwellings in Arizona. Water was and is an important resource in the desert. The native americans irrigated their crops using water from this natural spring. Unfortunately, the water was not the purest, being high in carbon dioxide and arsenic. The well is a unique ecosystem with several plants and animals found nowhere else on earth. There are leeches, amphipods, water scorpions and turtles. I don't ever want to see a water scorpion! https://en.wikipedia.org/wiki/Montezuma_Well
