The Seven Rila Lakes are a group of glacial lakes in the northwestern Rila Mountains in the Southwest of Bulgaria. The lakes are situated between 2,100 and 2,500 metres elevation above sea level. Each lake carries a name associated with its most characteristic feature. The highest one is called Salzata ("The Tear") due to its clear waters that allow visibility in depth. The next one in height carries the name Okoto ("The Eye") after its almost perfectly oval form. Okoto is the deepest lake in Bulgaria, with a depth of 37.5 m. Babreka ("The Kidney") is the lake with the steepest shores of the entire group. Bliznaka ("The Twin") is the largest one by area. Trilistnika ("The Trefoil") has an irregular shape and low shores. The shallowest lake is Ribnoto Ezero ("The Fish Lake") and the lowest one is Dolnoto Ezero ("The Lower Lake"), where the waters that flow out of the other lakes are gathered to form the Dzherman River. They are one of Bulgaria’s most popular tourist attraction, visited by nearly 500,000 every year.