Way up in northern California, Lava Beds National Monument is a land scarred by the tectonic grumblings of the Medicine Lake shield volcano nearby. Millions of years of lava pouring through the land resulted in a labyrinth of 800 caves. Twenty of these caves host strange and surreal ice formations during winter, the most spectacular of which is Crystal Ice Cave. Like something straight out of a Norwegian novel, Crystal Ice Cave brims with rare ice formations that can’t help but make you say “Oooooh.”

The cave drops as deep as 150 feet below the ground and runs 960 feet long, and features towering ice stalactites, stalagmites, and two frozen waterfalls, according to the Mail Tribune. The formations are different each year, depending on how the water falls and freezes. The cave was named by Judson Dean Howard, who is credited for prodding President Calvin Coolidge to turn the caves at Lava Beds into a National Monument. The land above Crystal Ice Cave is a desert, and the drippings from the cave’s formations offer a crucial watering hole for wildlife. 

The cave is usually accessible via private tours on Saturdays from January through March, which can only be booked over the phone and tend to fill up fast, according to Gizmodo. At one point, the ice cave tours took as many as 40 people—until rangers noticed the tours caused an enormous, unnatural spike in temperature and reduced the group size to six. Would-be cavers must provide their own spelunking equipment, pass a screening for white-nose syndrome before entering the subterranean system, and be able to ascend a 50-foot long ice slope on a rope, among other hazardous physical maneuvers.

In recent years, as the area has experienced warmer winters, Crystal Ice Cave seems to be melting, according to a short video from the National Parks Service. The Parks Service did not open Crystal Ice Cave tours in 2020 due to  high temperatures, which prevent the monumental ice formations from freezing and leave areas of the cave wet and too dangerous to traverse.

Lava Beds National Monument is located on the ancestral lands of the Modoc people. Some white settlers who colonized the region demanded the Modoc people be forcibly removed to the Klamath Reservation in Oregon, which had poor conditions and was also occupied by members of the Klamath, Yahooskin, and Paiute Tribes, according to a National Parks Service report. In 1870, a group of 372 Modocs left the reservation and returned to Lava Beds, taking refuge in a natural lava fortress and holding off the U.S. army for five months.