That's also why you can snorkel or dive year round and never feel cold. You'll see ancient rock formations and fossils inside the limestone and large gold fish swimming by. Visibility is always good, between 60-100 feet.
This spring is truly an archeological site where several remains of extinct animals from the Pleistocene where found. They even found bones of early men from as far back as 75,000 years B.C.
The Devil's Den is open for snorkeling or scuba diving Monday-Thursday from 9:00AM-6:00PM and Friday-Sunday from 8:00AM-6:00PM.
All equipment can be rented on the premises.
More information at Devil's Den - Florida's Pre-historic Spring