Discovering Arizona's Secret Underground Cavern Trail Where Few Travelers Ever Venture

About 675,000 years ago, hot lava carved a mile-long tunnel under the pine forest near Flagstaff, and today you can walk right through it. Once you pass the boulder-filled mouth, the temperature plummets and the desert heat vanishes behind you. Turn off your light and the darkness swallows everything, even your own hand. It’s one of Arizona’s coolest adventures, and plenty of locals still have no idea it exists. A Lava-Carved Tunnel Beneath the Coconino Forest © Lava River Cave, Flag