city, western Slovenia, on the Pivka River northeast of Trieste (Italy). Long a local market centre, it is on the rail line and road from Trieste to Ljubljana, the capital of Slovenia. Its prime importance is as a tourist centre for its Postojna Cave, an internationally famous cave system considered to be Europe's best example of karst phenomena-heavily and irregularly eroded limestone structures and underground streams. References to the town date from the 13th century, and it became a borough in 1432. It became a city in 1909. Postojna is a regional educational and cultural centre and has light industry.
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