The temple stands on the rim of a caldera, and the caldera is vast. Mount Batur, in the north-east of Bali, sits inside a ring of cliffs some ten kilometres across, left by two huge eruptions tens of thousands of years ago, and in the bowl lies Lake Batur, a crescent of dark water. Pura Ulun Danu Batur is the second most important temple on the island, dedicated to Dewi Danu, the goddess of the lake, whose waters feed the springs and irrigation canals that run down the mountains and water the rice fields of the south. For Balinese farmers, this is where the water comes from, and offerings are made here to keep it flowing.
The temple has a violent history. In 1926 Mount Batur erupted and buried the old village of Batur, and the people believed that the lava stopped at the gate of the temple, leaving it untouched. Afterwards the villagers moved up to the rim and rebuilt the temple there, in a complex of gates, shrines and multi-roofed towers called merus, each with eleven roofs for the lake goddess. UNESCO listed the temple and the whole subak system of rice terraces in 2012 as a cultural landscape. The subak is a farmers' cooperative that shares water by religious calendar and consensus, an arrangement older than any government.
Kintamani, the village on the rim, is cool, often misty, and known for its views over the volcano and lake. The smell of woodsmoke and clove cigarettes drifts on the air, and the coffee is good. Dress properly for the temple, with a sarong and sash, available to hire or borrow at the gate, and expect to pay a small donation.
Riding here means mountain roads. From Ubud the road climbs through villages and forests to the rim with a long series of bends, and traffic can be heavy with tour buses and scooters. Surfaces vary, and rain can come suddenly in the afternoon. Mornings are clearest. Fuel is available in Kintamani and the larger villages along the road, and many small shops sell fuel in bottles. The dry season, from May to September, is the best time.