Date: Tue Aug 25 00:04:28 EDT 1998
Subject: A.Word.A.Day--karst
karst (karst) noun.

An area of irregular limestone in which erosion has produced fissures,
sinkholes, underground streams, and caverns.

[German after the Karst, a limestone plateau near Trieste.]

They occur in many areas. In U.S., Kentucky and Florida.
The Pleasure Dome of Kubla Khan was built over one.