Nová rasovna, Underground cave system in Holštejn, Czech Republic

Nová rasovna is a cave in the northern part of the Moravian Karst, on the left side of the Hrádský (Holštejn) ravine near Holštejn, where the Bílá voda stream sinks underground. Its passages run through several levels, and since 2023 it has been linked to the Lipovecká ventarola cave through the Jiná dimenze dome, bringing its total length past 2 km.

Exploration started in 1833 when two miners descended into the underground passages at Count Salm's request. Their early observations laid the groundwork for understanding this karst system.

Geological formations inside carry names from their discoverers, such as the Vaňous dome named after a local miller who found it. These names connect the cave to the people who explored its passages and shared what they saw.

The cave is not a show cave: entry is for cavers only, and the lower levels are reached by rope ladders installed between 1973 and 1978 and later rebuilt in metal. The Bílá voda sinks here, so passages flood during high water; the Macošský siphon was first swum by divers in 1985. The road bridge above the sinkhole was built because passing vehicles were loosening the rock wall.

The underground waters connect with the Bílé vody stream, which flows through the lower levels and eventually becomes the Punkva river. This hidden water route is a key part of the region's water system.