Lake Canterno, located in the heart of Ernici, is a karst lake. Originally it filled when a sinkhole, through which water flowed into the ground, was blocked by debris. When the rising water pressure caused the sinkhole to reopen, the lake then returned to empty. This natural cycle was interrupted when the sinkhole was artificially closure for the production of electrical energy. The lake is not suitable for swimming and the water level is very dependent on the rainfall period.