Photograph by Chris Bickford, National Geographic Travel

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Fifteen coastal dune lakes, which are globally rare, formed along the Walton County coast in the northwest region of the state.

Photograph by Chris Bickford, National Geographic Travel

Florida by Land: Explore Geological Wonders

Visit caverns, sinkholes, and other often rare and unexpected wild spaces in Florida.

To see how Florida was formed—and continues to be shaped—by forces of water and wind, visit caverns, sinkholes, and other often rare and unexpected wild spaces. Whether underground or hiding in plain sight, these natural ecological treasures provide opportunities for exploration and a living link to the past.

Florida Caverns State Park, Marianna

Dazzling formations of limestone stalactites, stalagmites, soda straws, flowstones, and draperies are hidden beneath the surface of Florida Caverns State Park. This is the only state park in Florida offering public cave tours (closed Tuesdays and Wednesdays). “Florida Caverns is a geological wonderland,” says park manager Chris Hawthorne. “Karst topography underlines the park, an array of formations can be viewed in the cave, and the park’s buildings feature limestone hand-carved by the Civilian Conservation Corps during the Great Depression."

Devil’s Millhopper Geological State Park, Gainesville

It’s 232 steps down to the bottom (and 232 back up to the top) of Devil’s Millhopper, a 120-foot-deep limestone sinkhole. Preserved within the walls of this bowl-shaped cavity is a geologic record of central Florida’s past. Marine animal shells in lower layers are remnants of an ancient sea, and the fossilized bones and teeth of extinct animals have been found at the base. If the hike back in time is too strenuous, stay at the top and see views of the bottom in the Visitor Center. Afterward, walk the half-mile nature trail circling the sinkhole rim. Closed Mondays and Tuesdays.

Coastal Dune Lakes, Walton County

Drive Scenic 30A along the Walton County coast and you’ll be treated to a rare sight: 15 coastal dune lakes, the highest concentration in the world. The shallow lakes, which have been identified as globally rare, are surrounded by white-sand dunes (up to 30 feet high). Although a sand embankment separates the mostly freshwater lakes from the saltwater Gulf of Mexico, the two do mix intermittently. Outflows of lake water into the Gulf result in inflows of salt water into the lake. Get an up-close view of the lakes—and of ospreys, great blue herons, bald eagles, and other wildlife—by hiking the dune walkways at four state parks: Camp Helen, Grayton Beach, Topsail Hill Preserve, and Deer Lake.


When to Go: Florida Caverns State Park opens at 8 a.m. Cave tours can sell out (no advance ticket sales), so morning visits are best. Before heading to the park, call the ranger station (850-482-1228) to see if tours still are available for that day.

Fun Fact: The Devil’s Millhopper earned its name from the fossilized animal remains found at the bottom of the sinkhole. According to local legend, the sink fed bodies to the devil in the same way a funnel-shaped hopper fed grain into a gristmill grinder.