This National Park Has the Longest-known Cave System in the World—With Over 400 Miles of Passages and a Frozen Waterfall

This National Park Has the Longest-known Cave System in the World—With Over 400 Miles of Passages and a Frozen Waterfall

Along with underground adventures, Mammoth Cave National Park in Kentucky offers great hiking and kayaking, too.Credit: Courtesy of Mammoth Cave National ParkKey PointsLocated in Kentucky, Mammoth Cave National Park is home to the world's longest-known cave, extending for more than 400 miles.While exploring the cave system on guided or self-guided tours is a popular activity, the park's forests and rivers are great for outdoor recreation like hi…