Rebecca J. Rosen, writing for the Atlantic Cities:
Here’s what’s going on underground: the entirety of Florida sits on a bed of limestone, covered in varying degrees by composites of sand, clay, and soil. Limestone is soluble and porous, and over millions of years, acids in water have sculpted out a network of subsurface voids beneath the Floridian ground (think: Swiss cheese).
What Rosen doesn’t mention—but should—is that most of Florida south of Lake Okeechobee is basically a river we call the Everglades.