Sinkhole in Winter Park, Florida

In May of 1981 this sinkhole opened in Winter Park near Orlando.  Sinkholes, found in carbonate rocks such as limestone, dolomite, and marble (sometimes rock salt and gypsum too), form when the underlying structure is dissolved.  Human activity also has a large impact on the formation of sinkholes.  Water withdrawl decreases the buoyant support of "roofs" allowing soils and rocks to ravel into caverns.  Landscapes littered with sinkholes are referred to as karst terrane, after the Kars limestone plateau in Yugoslavia.  Note in this photo the travel trailer to the left and the power line still suspended over the sinkhole.