[scott]

Bloodpearl 13,

I'm not a geologist (I'm a CPA) so don't take my definition as gospel. In Florida, below ground is the Floridan Aquifer- where we get our drinking water from and from which our many springs bubble out of. When the ground above the aquifer is weakened (for a variety of reasons) it collapses into the aquifer and forms a sinkhole. Flow from the aquifer, rain, runoff, etc. fill the hole with water and you've got a place to dive in.

That's my limited understanding and I welcome any corrections or comments.

Scott

P.S. Nothing really special about them to dive in other than that some of them are very deep.