Križna jama, Cross Cave, is the one that limits its own visitors on purpose, and that decision is why it is worth the trip.
It lies in Slovenia's Lož Valley between the Lož and Cerknica karst fields and the Bloke Plateau, named after the nearby Holy Cross Church at Podlož. It is also called Mrzla jama pod Križno goro, the Cold Cave under Cross Mountain. What it is known for is a chain of subterranean lakes.
The formations here grow at up to 0.1 mm a year, which is glacially slow even by cave standards, and they are correspondingly fragile. Rather than harden the cave for volume, the people who look after it cap visits to the flooded section at four people a day. The result is that Cross Cave is among the best preserved caves open to the public anywhere in Slovenia.
Care of it has passed down a line of volunteers: prepared for visits in the 1950s by the Lož Valley Tourist Association, later managed by the Ljubljana Cave Research Society, and since the 1990s looked after by the Friends of Cross Cave Association.
It is also an ecological site of the first rank. Forty five species live in it, some not described until after 2000, which makes it the fourth richest cave ecosystem in the world for biodiversity.
It was first documented in 1832, but the lakes and stream passages were not explored until Slovene cavers reached them in 1926. The water is still in charge: on 6 January 2024 five people were trapped inside by floodwater after heavy rain, and were brought out on 8 January.
Slovenia
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