Juniper Springs Recreation Area is located in Florida's Ocala National Forest. The swimming area, trails, and campground were constructed by Civilian Conservation Corps in the 1930's. I think they describe it well on their website:
"The setting is unlike any other found in the United States, with hundreds of tiny bubbling springs and massive springs gushing out of crevices in the earth beneath a dense canopy of palms and oaks, an oasis within the heart of the desert-like Big Scrub."
There were 3 or 4 different types of turtles of pretty good size...
Juniper Spring was a very unique and fascinating experience - a good place to relax, swim, hike, and kayak (if you're very experienced).