Catacombs Cave, a lava-tube cave in Lava Beds National Monument in northern California, is known for its unusually intricate network of branching passages, sharp turns, lava falls, and multiple levels rather than one main chamber. Formed by smooth lava flows about 10,500 to 65,000 years ago, it was named by J. D. Howard, who thought its many side passages resembled Rome’s catacombs. The cave begins with a relatively easy stretch, but soon becomes extremely low and difficult, with much of the system blocked or constricted. Popular yet hazardous, it was the site of a major 2004 rescue after two children were lost inside for 27 hours.