Zbrasov aragonite caves

The Zbrašov Aragonite Caves (Zbrašovské aragonitové jeskyně) are a national nature monument in Teplice nad Bečvou in the Olomouc Region, Czech Republic. The main object of its protection is a hydrothermal karst area of European importance. It includes the aragonite caves as well as the surrounding forests. Discovered in 1912 and opened for the public in 1926, the caves were created by both surface water and underground mineral water springs rich in carbon dioxide, that are also used in the spas of the nearby village and spa resort of Teplice nad Bečvou. The caves are filled with formations of stalagmite and aragonite that resemble geysers and doughnuts, and the bottom levels of the caves are filled with carbon dioxide. The temperature stays around 14 °C (57 °F) throughout the year, making the caves the warmest underground area in the Czech Republic.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).