Fodor's Expert Review Mammoth Cave National Park

Spanning a distance of more than 400 miles, Mammoth Cave is the longest cave system in the world, and the best place to experience a little stretch of this massive system is Mammoth Cave National Park. As Cave City's biggest attraction, it draws hoardes of tourists, and summertime cave tours can get crowded. The U.S. National Park Service offers a range of themed tours throughout the year to different sections of the cave, ranging from an easy quarter-mile to a physically demanding six-hour exploration. For safety reasons, backpacks and baby carriers are not allowed inside the caves.