Jewel Cave National Monument contains Jewel Cave, currently the third longest cave in the world, with 200.3 miles of mapped passageways. Frank and Albert Michaud, two local prospectors, discovered the cave in 1900, when they felt cold air blowing out of a small hole in a canyon. The hole was too small for a person to enter so the brothers dynamited the entrance to make it bigger. They found a cavern lined with calcite crystals naming it “Jewel Cave”. Theodore Roosevelt proclaimed Jewel Cave National Monument in 1908. Access to the cave can be reached now via an elevator as well as a cave tour by foot. There are also three surface trails.