The Bromo Tengger Semeru National Park is located in East Java, Indonesia, to the southeast of Surabaya, the capital of East Java. It 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 m. The Tengger Sand Sea has been protected since 1919. The Bromo Tengger Semeru National Park was declared a national park in 1982.
The area in and around the park is inhabited by the Tengger people, one of the few significant Hindu communities remaining on the island of Java. The local religion is a remnant from the Majapahit era and therefore quite similar to that on Bali but with even more animist elements. The Tengger people are believed to be descendents of the Majapahit empire and were driven into the hills after mass arrival in the area of Muslim Madurese in the 19th century.
The Tenggerese are basically either agriculturalists or nomadic herders. The agriculturalists generally live on the lower altitudes, while the nomads live on the higher altitudes, riding on small horses.
I had marked on this map below some of the spots that I had taken my photographs from for your reference. The yellow line marks the caldera border from the ancient volcano.