Lake Van holds water so charged with soda that people here once washed their laundry in it without soap. The lake has no outlet: as the Nemrut volcano grew across the basin's drainage some 600,000 years ago, the water was sealed in, and evaporation has left its carbonate behind ever since. It is the largest soda lake on Earth — 3,755 square kilometres, 451 metres deep, 1,640 metres up on the Anatolian plateau, and alkaline enough (pH 9.8) that it barely freezes in winter. Almost nothing lives in it. One fish does: the pearl mullet, found nowhere else, and even it cannot breed here. Every May and June it runs out of the lake and up the freshwater streams, hurling itself over the rapids at Muradiye, because its eggs would die in the soda. In the shallows, cyanobacteria have built the tallest carbonate towers known to science.
Akdamar island carries the lake's one great human landmark: the Church of the Holy Cross, raised in pink-red tufa between 915 and 921 for Gagik I, king of Vaspurakan. Its outer walls are carved the whole way round — David swinging at Goliath, the great fish giving up Jonah, grape pickers tangled in vine scrolls — a Bible worked into stone. Boats cross from the Gevaş jetty in twenty minutes; you read the wall panel by panel, then sit under almond trees that flower white across the island in April. Restored in 2005–06, the church has been a museum since 2007, and one day each September a Divine Liturgy is sung inside it again. Wade in from the shore and the water is the surprise: less salty than the sea, yet slippery and faintly soapy on the skin. The lake is shrinking, though: drought has pulled the level down through the 2020s, uncovering the stone causeway that once ran out to Çarpanak island.