Zbrašovské Aragonite Caves

The Zbrašovské Aragonite Caves are a protected area in the Přerov District, Czech Republic, that were proclaimed as a National Natural Landmark to protect important hydrothermal karst areas of Europe. They include 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 used in spas in 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 cave are filled with carbon dioxide. The temperature stays around 14 °C throughout the year, and the caves are the warmest underground places in the Czech Republic.

Source: Wikipedia