Lake Sevan is the largest lake in the Caucasus, and the ninth-century monastery that made it famous was built on an island that is no longer one. The water fills a bare volcanic basin 1,900 metres up in eastern Armenia, wide enough that from most of the shore you cannot see across it. From the 1930s Soviet engineers tapped it for irrigation and power; the level went down by about twenty metres, and the island of Sevanavank came ashore as a peninsula. You climb a stepped path to two churches of dark volcanic stone, put there in 874 by Princess Mariam, not as an honour but as a place of penance for monks who had erred, on a rock that could then only be reached by boat. The wind on the black terrace never drops, and from there the water runs flat to the edge of sight.
Boats go out from Sevan town into the middle, where the peninsula and the bare hills line up behind you and the shore disappears altogether. Fed straight off the mountains, the lake keeps its bite even in August, and you get in and out fast rather than linger. On the western shore at Noratus stands the largest field of khachkars left in Armenia: close to a thousand carved cross-stones across seven hectares of grass, the oldest from the late tenth century, and no two alike. What gets grilled along the water is ishkhan, prince, a trout that lives in this lake and no other. It came in four kinds, each breeding in its own stream, and the draining wrecked the streams. Two of the four are gone for good, and most of today's catch is a whitefish brought from Lake Ladoga in the 1920s that thrived in the warmer, shrunken water. The lake is being paid back: much of the water arriving now never fell in this basin but is carried under the mountains from the Arpa valley through a tunnel opened in 1981, and the level has been climbing. The water could be brought back through a mountain. The fish could not.