Weaver's Cave, Natural cave in Rakov Škocjan Valley, Slovenia

Weaver's Cave is a 2,885-metre ponor cave in southwest Slovenia, entered from the west side of the Rak Škocjan Valley through two entrances. Rak Creek runs through it and continues into Planina Cave. A metre-wide constriction 450 metres from the entrance narrows the passage.

Johann Weikhard von Valvasor first documented the cave in 1687 in the Philosophical Transactions of the Royal Society. This early scientific record made it one of the first cave systems in the region to gain wider recognition.

The cave is named after a stalagmite that resembles a weaver. An old story says the weaver was turned to stone for working on Sunday, the Lord's Day. The name Tkalca jama means 'weaver's cave' in Slovene.

The lower entrance offers the main access point, and visitors should bring appropriate footwear due to constantly wet and slippery conditions inside. Warm clothing is advisable since the temperature remains cool year-round.

A one-metre-wide constriction 450 m from the entrance throttles flood discharge; when rain coincides with snowmelt, water backs up and flood marks rise up to 19 m above the cave lip. Dye tracer tests show that nearly all water entering the cave resurges 2.8 km downstream in Planina Cave.