The Sand Cave Trail at Mammoth Cave National Park in Cave City, Kentucky is an easy 0.2 mile out-and-back boardwalk trail that leads out to the Sand Cave lookout point.
Sand Cave, while it lies within the national park, is not connect to Mammoth Cave, so it's its own separate cave. Sand Cave became a national newspaper sensation in the January 1925 when Floyd Collins, a well-known American cave explorer, became trapped in a crawlspace 55 feet underground. He was in search of a new entrance to Crystal Cave, which is a cave that lies on his old property. The rescue team was unable to get him out of Sand Cave and after 14 days underground, he died.
Waterfalls: During the Spring and after heavier rainfalls, you can find a small waterfall spilling over the cave entrance.