If you’ve ever wondered what’s directly beneath your feet, YouTube channel Across the Globe has done the digging for you. Their new video takes a look at the deepest cave, mine, borehole, or sinkhole in all 50 states, and there’s some genuinely wild stuff underground in the United States.
There are some pretty unique and fascinating caves out there, including Hawaii’s Kazamura Cave, the deepest lava tube on the planet at 3,614 feet. It’s accessible through a local guy’s backyard, and he’s been running tours from his carport since 1996. Oklahoma drilled a borehole nearly six miles deep in 1974, hit molten sulfur, snapped the drill bit, spent $7 million, and found nothing valuable. Montana’s Tears of the Turtle is so remote that rescue is considered basically impossible if something goes wrong, which feels like important information to have before you go.
Some entries lean more toward cautionary tale. Florida’s Mystery Sink is a 500-foot water-filled abyss sitting behind a suburban fence off Interstate 4, where two divers disappeared in 1970 and were never found. Georgia’s Ellison’s Cave has claimed three lives since 2009. Louisiana’s Diamond Crystal Salt Mine was accidentally flooded in 1980 when an oil rig punched through its roof, draining 3.5 billion gallons of lake water underground in about three hours.
On the lighter end, South Carolina’s failed railroad tunnel became a cheese cave. New Jersey’s deepest mine was used as a film set for Zoolander, and Kentucky’s Mammoth Cave once hosted a tuberculosis hospital inside it, which did not work. Make sure you watch the full video if you’re curious about your own state.
