A team of scientists from the Czech Republic has discovered the world’s largest underground thermal lake, located in southern Albania. They first stumbled upon the lake (and the elaborate cave system it’s a part of) in 2021, but didn’t have the proper equipment to properly study it, according to a press release.

Researchers discovered the body of water—now the largest known underground thermal lake in the world—while investigating a column of steam rising from limestone.

Czech researchers confirmed the existence of the world's largest underground thermal lake, named Lake Neuron, in southern Albania, first discovered in 2021. The recent expedition utilized measuring tools to determine the lake's dimensions and volume.