Not far from the village of Bosnek located 40 km from the capital Sofia, flows a miraculous spring in whose waters many people seek healing and solace. It is also known as the Fountain of Happiness after Ottoman traveller Evliya Celebi gave it this name in the 17^th century. The water gushes out from the mouth of a stone crocodile and does not flow constantly but at intervals, following a form of logic that no one has yet figured out. Sometimes it stops for hours, other times just for several minutes. According to one legend, the spring runs dry when a sinner stands before it and gushes out when a righteous person approaches. Near the spring is the longest cave in Bulgaria - Duhlata.