My friend Adam and I recently visited Morrison Springs, a beautiful, crystal-clear spring located about 1.5 hours east of Pensacola. The exact location of the spring is Ponce de Leon, Florida buuuuut there isn't much to see there besides a couple of swimming spots -- it's best to stop here on a road trip through Florida or on a day trip from Pensacola.
The spring is surrounded by giant cypress trees and thick vegetation. Like most natural springs, the water is freezing at about 68 degrees and the best way to get in is to just do it quickly -- submerging one body part at a time only prolongs the chill.
One of the main attractions of Morrison Springs is the cave right in the center of the spring. It's a popular spot for cave-diving certified divers, but being rule-followers and also wishing to remain alive, Adam and I stuck to snorkeling. Super cool and totally freaky underwater views.
We swam around the opening of the cave and watched scuba divers enter and exit. Apparently, there are dozens of freshwater eels in the cave and of the three caverns, the deepest is 300 feet. The temperature of the water and the sight of the giant cave opening gives you a bit of a jolt -- quite a departure from the typical leisurely beach day. Definitely pack snorkeling gear (fins are particularly helpful) and towels to lay out on to warm up in the Florida summer sun (you'll be welcoming the heat after about 5 minutes in the water)!