Lava River Cave

Eighty thousand years ago, a river of lava drained out of its own tunnel and left a mile of empty corridor beneath what is now central Oregon. That corridor — the longest known lava tube in Oregon — sits 12 miles south of Bend inside the Newberry National Volcanic Monument, holding steady at 42 degrees year-round. Archaeologists believe Native Americans knew about it long before settlers; the first recorded discovery came in 1889. Bring two light sources. The cave does not forgive the unprepared.