Three sinkholes filled with warm, crystal-clear water reached by a horse-driven cart on an old train track through the jungle.

Natural saunas fed by volcanic heat.

Volcanically heated hot springs.

This conservation area is also home to many of the region's desert tortoises.

A volcanic tunnel illuminated by natural skylights offers a shaded respite from the desert sun.

A meditative space out of a fantasy story.

Its history includes dinosaur fossils, cattle rustlers, Georgia O'Keeffe, and a mythical giant rattlesnake named Vivaron.

A famous flea market artist's studio that's full of odds and ends.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

Some 10,000 works of ancient rock art cover these volcanic basalt outcrops near the Gila River.