Thanks to the myth of Ponce de Leon's trip, Florida—known for its large population of retirees—is now awash in "fountains of youth." Dozens of bodies of water claim the title of the one legendary fountain, from mineral springs to deep-water wells, not to mention water from a variety of sources that is piped into various built structures.

Only one, however, is known to be radioactive. And, oddly, it might be actually extending life.

In Punta Gorda, a town on Charlotte Harbor, a blocky, green-tiled fountain abuts an empty lot near the harbor. A spigot juts out near the top to release water from the artesian well below. Each of the four sides features a picture of a ship, a tribute to Ponce