1Mammoth Cave, Kentucky
Mammoth Cave National Park in Kentucky is home to the longest known cave system in the world, with more than 400 miles of explored passageways. The cave is filled with incredible limestone formations, underground rivers, and chambers. Visitors can explore the cave through guided tours, which range from easy walks through large corridors to more adventurous spelunking tours that venture deep into the lesser-known parts of the cave. Above ground, the park offers hiking trails, rivers, and rich biodiversity, making it a destination for both underground and above-ground exploration.
