Mount Bromo is a crater smoking without pause in a plain of grey ash in East Java, and for the people who live around it that vent is the centre of worship. The plain is called the Sea of Sand, and it is the floor of a much older volcano that collapsed. Bromo and its neighbours are younger cones that grew inside the wreck of it, with Batok's ribbed cone beside it and Semeru, the highest mountain on Java, standing behind them both. The classic view is from the Penanjakan ridge, and most of it is waiting. You are up there hours early in the cold dark, with nothing to watch but the sky slowly greying. Then the light arrives, and it arrives fast: the cones surface out of a sea of mist lying on the ash, and for a few minutes the caldera is gold. Calm dry-season mornings deliver it; from November to April cloud usually takes it away.
The jeeps cross the ash, but the hour it takes you on foot from the village of Cemoro Lawang is the better version. Faint tracks run over pale, wind-combed sand, frosted white before dawn in July and August. A whitewashed Hindu temple stands alone at the foot of the cone as you come up to it. A staircase up the flank ends on a rim barely a metre wide, a low railing along part of it and nothing along the rest. The vent roars and belches sulphur a few steps from you. The Tenggerese are Hindus on an island that is mostly Muslim, and their faith puts the volcano where Bali puts a temple. It goes back to a childless couple granted twenty-five children on the vow that the youngest would be given to the mountain. When they hesitated, the volcano took the boy itself, and asked for an offering every year after. Once a year, at Yadnya Kasada, they climb that same staircase and throw rice, fruit, chickens and money over the lip, while others wait on the inner slopes to catch what comes down.