The Bromo, or Mount Bromo is an active somma volcano and part of the Tengger mountains, in East Java, Indonesia. At 2,329 meters (7,641 ft) it is not the highest peak of the massif, but is the most active and famous. The area is one of the most visited tourist destinations in East Java, and the volcano is included in the Bromo Tengger Semeru National Park. The name Bromo comes from the Javanese pronunciation of Brahma, the Hindu god of creation. At the mouth of the crater, there is an idol of Ganesha, the Hindu god of wisdom which is being worshipped by the Javanese Hindus. Mount Bromo is located in the middle of a plain called "Sea of Sand", a nature reserve that has been protected since 1919.

Bromo Tengger Semeru National Park is a national park located in East Java, Indonesia, to the east of Malang and Lumajang, to the south of Pasuruan and Probolinggo, and to the southeast of Surabaya, the capital of East Java. It is the only conservation area in Indonesia that has a sand sea, the Tengger Sand Sea, across which is the caldera of an ancient volcano (Tengger) from which four new volcanic cones have emerged. This unique feature covers a total area of 5,250 hectares at an altitude of about 2,100 meters (6,900 ft). The massif also contains the highest mountain in Java, Mount Semeru, four lakes and 50 rivers. It is named after the Tengger tribe. The explosion of the volcano that created the caldera, happened ca. 45.000 years ago, in an event similar to the Krakatau eruption.