A twelve-ton boulder on the shore of Lake Pleshcheyevo, a shrine to the Merya people and then to the Slavs. The church fought it for centuries: it was buried, sunk in the lake, and hauled on a sledge to be used in a bell tower's foundation — the sledge went through the ice, and decades later the stone was back on the shore. There is a physical explanation too: ice movement and washed-out ground push the boulder up. The name comes from the colour, which turns blue when wet.