The Natural Entrance route is a self-guided tour available to visitors with plenty of time and in good physical condition. This 11/4-mile tour follows the traditional explorer's route, entering the cavern through the large historic natural entrance. The Natural Entrance route descends more than 750 feet into the earth following steep and narrow trails through a tall and spacious trunk passage called the Main Corridor.
Added by Upcoming Robot on September 9, 2010