These caverns are among the largest and most beautiful in the country, and because they are wet caverns, stalactites, stalagmites, soda straws, and other cave formations are still growing. Within the caverns are two huge rooms, each larger than a football field with ceilings more than 100 feet high. These two rooms can be visited on two separate tours. On the shorter Rotunda/Throne Room Tour, you'll see, in the Rotunda Room, thousands of delicate soda straws. The highlight, though, is the Throne Room, at the center of which is a 58-foot-tall column. The second, and longer, tour visits the Big Room and leads past many strange and rare cave formations. Within the park are several miles of aboveground hiking trails. A campground ($25 per night) provides a convenient place to stay in the area.

Because the caverns are a popular attraction and tours are limited, try to make a reservation in advance, especially if you want to visit on a weekend. However, it is sometimes possible to get same-day tickets.