Black Cave, Solutional cave in Municipality of Postojna, Slovenia

Black Cave (Črna jama) is a 3,294 m karst cave 3 km northwest of Postojna, entered at the bottom of a large collapsed doline reached by road via Veliki Otok. It forms part of the cave system of the underground Pivka river, with large halls and horizontal passages whose big dark stalactites gave the cave its name.

Much of the 3,294 m cave was already known in the Middle Ages, when visitors from Postojna were led into it; a historical document records the visit of Johann Weichart Valvasor. After the inner parts of Postojna Cave were discovered in 1818, the Black Cave drew less interest. Between the wars a tunnel linked it to the main part of Postojna Cave and to Pivka Cave, and speleologists later found natural connections with other parts of the system.

The cave's name comes from the large dark stalactites inside, though in 1793 its formations were described as "white as snow"; the black colour is attributed to smoke and soot from forest fires at the entrance over the centuries. The 1964 black-and-white film Ne joči, Peter attributes the cave's discovery to a boy named Peter who fell into it, and its best-known line is his question "A si ti tud' noter padu?".

The cave entrance lies at the bottom of a large collapsed doline, reached by road from Postojna past Veliki Otok. The cave is lit and arranged for guided tourist visits, and it also forms one of the entrances to the Piuca underground system.

The cave appears in the 1964 Slovenian black-and-white film Ne joči, Peter, where its discovery is credited to a boy named Peter who fell into it by accident. The film's best-known line is his question: "A si ti tud' noter padu?"