Perhaps Jewel Cave National Monument doesn’t sound very impressive. After all, it’s just a National Monument, not at National Park, right? Wrong. Jewel Cave is the third longest known cave system in the world. And the key word in that sentence is “known.” New passages of Jewel Cave are still being discovered and mapped. Once it’s all mapped, it quite possibly could turn out to be the world’s longest cave. Scientists have estimated the volume of the cave using airflow studies. They measure how much air the caves exhales when the outside pressure drops and vice versa. The parts of […]