Katerloch, Limestone cave in Naas, Austria

Katerloch is a show cave near Dürntal in the municipality of Naas bei Weiz, Styria, with the most dripstone formations of any show cave in Austria. Its roughly one-kilometre tour route drops 135 m in height. The entrance hall holds moss- and algae-covered sinter columns, the largest 22 m high with a 46 m circumference, and looks down into the 45 m deep Marteldom. The Fantasiehalle, 120 m long, up to 85 m wide and 18 m high, contains around 4,000 large dripstone structures reached by stairs.

The cave's later sections, the Zauberreich and Seeparadies, were discovered in 1955 by the research couple Hermann and Regina Hofer. Numerous cave bear bones found inside show the cave was used by bears long before that. The name refers to the Eulenkater, a male owl that flies in and out of the portal.

The cave takes its name from the "Eulenkater", the local term for a male owl that flies in and out of the entrance portal. The name is thus tied to the birds at the cave mouth rather than to a cat, despite what the German word suggests to outsiders.

Entry is only possible with a telephone booking made in advance. The guided route covers about one kilometre and climbs 135 m in height, with stairs and steps through the Fantasiehalle, so sturdy shoes and a reasonable level of fitness help.

The largest column in the entrance hall is 22 m tall and has a circumference of 46 m; from there visitors look down into the 45 m deep Marteldom. The cave also yielded numerous bones of cave bears.