A mesothermal spring in a lush green valley outside the major roman spa town just below the Balkan mountain range.
Hisarya is dipping in hot springs but all of the really hot ones are either relegated as drinking fountains of left inaccessible in decrepit spas. At the archeological site of the roman thermae efforts where made to keep the ancient pools, hot water and visitors well separated.
At around 30ºC it might not be the hottest thing in town but location-wise it does not get any better: Beautiful sheep trimmed grassy fields lined with lush solitary trees: This truly is the tantalizing cement ring filled with bubbling blue green algae rich water you have been waiting for on this sunny day.
Estestven izvor, Hisarya, Bulgaria: Low temperature but very appealing surroundings: Come visit in summertime picknick'n'dip. – bert