Kelimutu is a volcano on Flores, in eastern Indonesia, and its summit carries three crater lakes side by side, each a different colour and none of them keeping it. Over a few months a lake drifts from turquoise to green to black to red and back, on no schedule anyone has worked out. The photograph that sent you there is often of a colour that has since gone. Each basin is a vat of volcanic acid. Gas rises through the crater floors, sulphur and chlorine, keeping the water fiercely acidic and loaded with dissolved iron, and every shift in that chemistry turns the minerals a different shade. Two of the lakes are separated by one thin wall of rock, close enough that a turquoise one can sit an arm's reach from a black or blood-red one. The third lies apart in a crater of its own. For the Lio people in the villages below, the three are where the dead gather: elders in one, the young in another, the restless and the wicked in the third.
The road up from Moni is driven in the dark, and the last stretch is a short walk to the rim, cold and windy until the sun reaches you. Mist sits in the craters and pulls back slowly, so the lakes come out one at a time. The paths link all three basins, and the place to stand is the narrow wall between the neighbouring two, with a different colour below you on either side. Between November and April cloud settles into the craters and a dawn can show you nothing at all. Instead of driving back down, a path leaves the summit grassland for montane forest, then threads between smallholdings of coffee and cocoa to the rice terraces around Moni. Once a year the rim is not a viewpoint. On 14 August the Lio villages climb the mountain with food and lay it along the crater edge for their dead, and whoever came up for the sunrise finds that the morning belongs to them.