Chevé Cave
Chevé Cave ( ; ) is a deep cave located in the Sierra Juárez mountain range in the southern Mexico state of Oaxaca. As of 2003, its deepest point has been measured at deep, making it the second deepest known cavern in the Western Hemisphere and the world’s 12th deepest cave. The cave's deepest known point is nearly one vertical mile and seven horizontal miles from the entrance, ending in a terminal sump. The present limit of exploration in Chevé, at 9.3 kilometers from the nearest entrance, represents one of the most remote locations ever attained inside any cave on Earth. The logistics of reaching this point are enormous: more than two kilometers of rope need to be rigged and three underground camps established. Chevé is the deepest proven freshwater hydrological system in the world. Temperatures in Chevé are moderate, ranging from . It has been most thoroughly explored under the leadership of caver Bill Stone.
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.