Caves can get pretty deep. One of the deepest known caves is the Krubera Cave, which plunges around 2,200 meters, or 7,217 feet, into the ground, or around the depth of six stacked Empire State Buildings. But how deep can caves actually get? MinuteEarth dove into the subject in a recent video released on September 19th, 2025.
Caves form as slightly acidic water seeps into cracks in soluble rock, typically limestone, gradually widening them into caverns. Three factors limit how deep caves can go: the depth of soluble rock, sea level, and the pressure from overlying rock. Krubera benefits from a thick limestone layer, unlike Mammoth Cave, which reaches only 118 meters due to its shallow soluble layer.
Caves generally form at the water table, which aligns with sea level, so Krubera’s high entrance allows its impressive depth while staying above the nearby Black Sea. Beyond roughly 2500 meters, the weight of rock above crushes limestone caves, capping their depth.
Human-made excavations, like a 4000-meter-deep South African mine reinforced with steel and diamond-coated rebar or the 12-kilometer Kola Superdeep Borehole, surpass these natural limits by drilling through non-soluble rock and withstanding extreme pressure, achieving far greater depths through engineering ingenuity.
