Batman has the bat cave. Some folks in Middle Tennessee had the weed cave. A short description:

Law enforcement officers in Tennessee make the greatest underground discovery since Tutankhamen’s tomb was unearthed in the Valley of the Kings. Under this ordinary house is a marijuana grow-op unlike any you have ever seen. Within the caves of middle Tennessee, growers constructed a complex of offices, living quarters, restroom facilities, and a climate-controlled forest of over one thousand cannabis plants.

The design on this thing was pretty extensive...check out the pics here. It looks like some keen minds were being used for misguided purposes.

(HT - Challies)