Sinkholes are one of the main landforms in karst topography, so named for the region in Yugoslavia where solution features such as caves, caverns, disappearing streams and hummocky terrain predominate. Karst features occur primarily in limestone but may also occur in dolomite, chert, or even gypsum (Alabaster Caverns in Oklahoma).

As the name implies, sinkholes are depressions formed by solution enlargement or the subsidence of a cavern roof. Subsidence may occur slowly, as the cavern roof is gradually weakened by solution, or rapidly as the roof collapses. Several of the latter occurrences have gained widespread coverage because of the size and amount of property damage involved.

An often-described sinkhole formed during May 1981 in Winter Park, Florida, swallowing a three-bedroom house, half a swimming pool, and six Porsches in a dealer's lot. The massive "December Giant" occurred near Montevallo, Alabama, and measured 400 ft (122 m) wide by 50 ft (15 m) deep...