The name tells you what matters here. Pura means temple. Ulun means head or source. Danu means lake. Pura Ulun Danu Batur is the Temple of the Lake's Source -- a shrine to the waters that sustain Bali's rice paddies, its agriculture, its life. Established in the 17th century, the temple is dedicated to the god Vishnu and to Dewi Danu, the goddess of Lake Batur, the island's largest body of freshwater. As one of the Pura Kahyangan Jagat -- the temples responsible for maintaining harmony across all of Bali -- it represents the cardinal direction of north and anchors the island's spiritual geography. The word batur itself, after the village where the temple was first built, means pure or spiritually clean. Ancient palm-leaf manuscripts called lontars list it among the sad kahyangan, the six universal temples of Balinese Hinduism.

The relocation after the 1926 eruption was a communal effort of remarkable scale. Villagers from Desa Bayung, Tunggiran, Kedisan, Buanan, and Sekardadi came to help. The Dutch Indies government dispatched the Bangli regional army and even prison laborers. The temple's gamelan -- the bronze percussion ensemble essential to Balinese ceremony -- was carried to a special pavilion in Desa Bayung for safekeeping. A guardian spirit figure called Bhatara Gede was transported to another village so residents could continue worship during the resettlement. Land on the caldera rim was parceled out to the original families, with local police officials called mantri polisi overseeing the distribution. Houses and infrastructure went up first, then the Bangli regional government raised a second fund to build the new temple. When it was completed, the gamelan and the Bhatara Gede were brought back in a ceremony that reunited the sacred objects with their home and cleansed everything -- instruments, shrine, and ground -- for the new beginning.

Pura Ulun Danu Batur is not a single building but a compound of nine separate temples containing 285 shrines and pavilions. The principal temple, Pura Penataran Agung Batur, is organized across five courtyards that progress from the public outer sanctum (jaba pisan) through a middle zone (jaba tengah) to the innermost sacred courtyard (jero). Its dominant feature is the 11-tiered meru tower -- the same shrine that survived the 1926 eruption -- dedicated to Shiva and his consort Parvati. Three additional nine-tiered merus honor Mount Batur, Mount Abang, and Ida Batara Dalem Waturenggong, the deified king of the Gelgel dynasty who ruled from 1460 to 1550. The eight surrounding temples serve more specific purposes: Pura Tirta Bungkah for the hot springs, Pura Taman Sari for gardens, others for agriculture, crafts, and holy springs.

The temple's significance extends far beyond ritual. Bali's subak system -- the cooperative water management network that distributes irrigation across the island's rice terraces -- is coordinated in part through temple ceremonies. Pura Ulun Danu Batur sits at the top of this system, spiritually and hydrologically. The lake it guards is the island's primary freshwater source, feeding the springs and rivers that supply the subak channels downstream. In 2012, UNESCO inscribed the Cultural Landscape of Bali Province as a World Heritage Site, recognizing the subak system and four associated temples, including Pura Ulun Danu Batur, as a manifestation of the Tri Hita Karana philosophy -- the Balinese principle of harmony among people, nature, and the divine. The temple's annual odalan festival, held on the tenth full moon according to the Balinese calendar, typically falls in late March or early April, drawing worshippers from across the island to honor the waters that keep Bali alive.