Most Joshua Tree visitors hike through the desert and see the boulders from the outside. This experience takes you somewhere different. Caves & Corridors is a guided scramble through the hidden world inside Joshua Tree's granite formations. You'll move through narrow slot passages, cathedral-like chambers, and natural rock corridors that most visitors never know exist. Your guide leads you through a sequence of named secret locations — each one chosen for its character, challenge, and sense of discovery. Summit Climbing Guides is the only guide service in Joshua Tree to offer Caves & Corridors as a dedicated experience — and the only one with the Summit Squeeze Scale, a custom rating system that tells you exactly how tight each passage gets before you commit. No surprises. This is not rock climbing. No prior experience is required. If you can hike and are comfortable with enclosed spaces at varying levels of tightness, this experience is for you. Groups are kept to 12 guests maximum so your guide can give everyone individual attention and select passages that match your group's comfort level.