One of the first things you'll notice when strolling into Corkscrew Swamp Sanctuary is a gradual drop in temperature. As the 2 ¼-mile boardwalk winds its way through an open prairie, a pine thicket, and finally into the largest forest of ancient bald cypress trees in North America, the air becomes refreshingly cool. "This season is one of the best times to visit," says executive director Ed Carlson. "There is an amazing competition among all the plants to determine which has the most beautiful leaves." The best secret, though, is that it's mosquito free, thanks to the resident mosquito fish that eat the larvae.