The Fiery Furnace in Arches National Park is a labyrinth of fins, pillars, hidden arches and narrow slot canyons. Explore it on spring or autumn days to enjoy the thrill of clambering through shady chambers and under soaring fins, but avoid it in summer when it truly earns its name. This inviting entrance greeted us on a late spring morning, with light bouncing back and forth among the rocky walls.