Boybuloq Cave
The cave is the deepest known cave in Asia having been explored to a depth of from the entrance. At the lowest discovered level a water-filled siphon blocks further exploration. It is thought that the cave has the potential to be the deepest known cave in the world, with a theorised depth of making it deeper than the Veryovkina Cave. The explored length of the cave is .
Gap Cave
Gap Cave is located just underneath Pinnacle Overlook in the Cumberland Gap National Historical Park, Lee County, Virginia. Currently, the cave has a surveyed length of 18.5 miles and is the 42nd longest cave in the United States and 154th in the world. There are six known entrances: the Gap Cave Entrance (also known as the King Solomons Cave Entrance), an artificial entrance, known as the Cudjo's Cave Entrance, the Stream Entrance, the Soldiers Cave Entrance, the Big Saltpeter Cave Entrance, and the Wellhole. All lead into the same cave, Gap Cave.