A stretch of the upper Vilyuy known to the Yakuts as Elyuyu Cherkechekh, the valley of the dead. Tradition places metal hemispheres in the ground there, warm inside, in which one can shelter from the cold — but whoever spends the night falls ill and dies soon after. The first written mentions of the cauldrons date to the nineteenth century. No expedition has found anything, including several in the 2000s with metal detectors; explanations range from outcrops of trap basalt to spent rocket stages.