Mount Bromo and the Tengger Caldera

According to the Smithsonian Global Volcanism Program, the Tengger caldera is a 16-km-wide structure at the northern end of a volcanic massif in East Java, with a history going back around 820,000 years. Bromo is its youngest and only active cone, and one of Java's most active and most visited volcanoes. It usually emits plumes of gas and steam, with occasional ash eruptions; a phreatic explosion in 2004 killed two people, and authorities periodically restrict access when activity rises.

The Sea of Sand has been protected since 1919. Bromo Tengger Semeru National Park was established in 1982 and covers about 50,000 hectares, managed today under the Ministry of Forestry. The Tenggerese, who live in the villages around the caldera, are a Hindu community; every year during Yadnya Kasada they climb to the crater rim to cast offerings into Bromo, a ceremony rooted in a 15th-century legend.

The Tenggerese are one of Java's few Hindu communities, and their villages on the steep slopes around the caldera grow vegetables such as potatoes, cabbages and leeks. Many families also work as jeep drivers, horse handlers and guesthouse hosts. The Yadnya Kasada festival, led from Pura Luhur Poten, draws large crowds, and during the sacred month of Wulan Kapitu Tengger elders observe rituals that can bring temporary limits on visits.