The men of Kawah Ijen walk three kilometres and 400 vertical metres up to the crater lip from the car park at Pos Paltuding, the location that tourists arrive at to begin their journey. From the crater lip, the workers descend into the crater and end up at an acidic aquamarine crater lake some 300 metres below, where big pipes funnel sulphuric gases so that water can be used to cool it down and thus solidify it.