Bromo Tengger Semeru National Park (Indonesian: Taman Nasional Bromo Tengger Semeru; abbreviated as TNBTS) is a national park located in East Java, Indonesia. It is the only conservation area in Indonesia that has a sand sea, the Tengger Sand Sea (Indonesian: Laut Pasir Tengger), across which is the caldera of an ancient volcano (Tengger) from which four new volcanic cones have emerged