Postojna is a town and a municipality in the province of Carniola, 22 miles from Trieste, in southwestern Slovenia. Near the town is a major tourist attraction: the 20-km long cave system called Postojna cave (Postojnska jama). The cave was first described in the 17th century by Janez Vajkard Valvasor, and a new area of the cave was discovered in 1818 by Luka Cec. Electric lighting was added in 1872, enhancing the cave system's popularity.