Devil's Millhopper Geological State Park in Gainesville centers on a dramatic sinkhole more than 100 feet deep into exposed rock layers, created as acidic groundwater dissolved limestone over long periods. About 120 feet deep and 500 feet wide, it contains twelve springs, a pond, cooler shaded air, and fossils including shark teeth, marine shells, and extinct land animals. Though only 71 acres, the park includes sandhill, hammock, and wetter habitats shaped by sun, fire, and water. Once used for University of Florida research, the site was bought by the state in 1974, designated a National Natural Landmark that year, improved for protected access, and later recognized for surviving Civilian Conservation Corps infrastructure.