The Devil's Millhopper is a 120-foot-deep sinkhole on the northern edge of Gainesville, and unlike most Florida sinkholes it is not full of water. Instead, a cool microclimate has developed inside the bowl — temperatures in the sinkhole run 10 to 15 degrees Fahrenheit cooler than the surrounding forest — and a lush, fern-filled rainforest environment has established itself on the steep walls and floor.
A wooden staircase of 232 steps descends to the bottom, where several small streams emerge from the limestone and cascade down the walls. The climb back up is a genuine workout in Florida's humidity. The state park is a few miles northwest of downtown Gainesville and is open most days; there is a small admission fee. The geology and the microenvironment together make it one of the more genuinely unusual sights in the state.