Overview

The world's largest known cave, Mammoth Cave has at least 360 miles of passageways and possibly hundreds more. Given the hundreds of thousands of people who visit this park each year, it's good that there's so much underground elbow room. Located about 85 miles south of Louisville, Ky., this 52,830-acre park offers visitors a wide variety of cave-touring options, from the tame to the potentially terrifying. Formed by water seeping through limestone over the course of 350 million years, the cave system has long been known to man: local Indians gathered gypsum and crystals here, and the cave was mined for gunpowder ingredients during the War of 1812. Modern visitors will find a mostly dry cave filled with stalactites and stalagmites as well as odd limestone formations. Tours can be as short as the quarter-mile Frozen Niagara Tour (named for one distinctly shaped formation) to Wild Cave tours than can take the better part of a day. The park also has more than 70 miles of hiking trails accessible on foot or by horseback, river paddling, and both established campground and backcountry camping by permit. Established: May 25, 1926 Area: 52,830.19 acres Website: [www.nps.gov/maca](http://www.nps.gov/maca)