Do you fear being in narrow or enclosed spaces? This route in the Utah desert, near Escalante, is a claustrophobe’s worst nightmare. Peek-a-boo Gulch is a slot canyon and a popular hike in the Grand Staircase-Escalante National Monument that cuts through sandstone bedrock as a narrow slit. Walls squeeze in on both sides. Hikers face interlinked potholes, tunnels, drops, fins of rock, and arches of stone silhouetted on blue sky. From the top, Peek-a-boo is a precipitous scramble into a crack, down small cliffs, inside potholes, and to a mandatory swim through a putrid pool near the canyon’s narrow mouth at the end.