Lake Sevan was the first place I visited outside of Yerevan during my stay in Armenia. The lake is one of the largest freshwater high-altitude lakes in the world but, unfortunately, was once on its way to becoming an ecological disaster along the same lines of the Aral Sea. In the 1930s, Soviet engineers decided to drain part of the lake and use the water for irrigation and hydroelectricity. As a result, the level of the lake fell by 19 meters, the surface area shrunk by nearly 200 square kilometers and the volume declined by 24 billion cubic meters. Luckily, the project was halted in the 1950s.
Lake Sevan is also home to the Sevanavank Monastery. Built on a uninhabited island in the lake in the 9th century, it now stands on a peninsula due to the falling water levels.