The first underground swimming relay was held in Poland at the Historic Silver Mine in Tarnowskie Gory. It’s on the UNESCO World Heritage List. The brave participants seem to love it!
“People who swim open water know what it means,” said one female swimmer. “This water is soft, you can feel it with the whole body, the experience is almost spiritual, it’s fantastic.”
Three hundred winter swimmers, known as ‘Walruses’ took part in the event which saw them swim through a 600 metre long rock corridor, 30 metres underground.See Euronews
Brave Swimmers Take Part in Polandâ€™s First Underground Relay | Euronews