In Thiafi Bay, large amounts of carbon dioxide and sulfur gas escape from rocks and cracks. The sulfur and various mineral salts are deposited on the rocks. Medicinal salts crystallize in a cave on the eastern edge of the bay. The most carbon dioxide gas escapes there. There is an acute risk of suffocation! Gases of up to 37 degrees Celsius also rise in the sea. Everything is on the fault zone that cuts Methana through and on which the spas are located in the main town of Methana. In Roman times there was also a spa and some archaeologists believe that it the Pausanias bath was here and not in Kato Mouska at the Agios Nikolaos settlement.