BLUE LAKE

It is located in the caldera of an extinct volcano. It is the largest of the four lakes in this area. The Blue Lake, with a surface of 70 ha and a depth of 72 m, supplies the city with drinking water. From December to March, the lake turns a cobalt blue color, turning grey from April to November. From the end of March, it regains a distinct dark blue color that persists until the following November. This phenomenon could be due to the temperature differences to which the limestone layers are subjected during the year.