Gunung Sewu (Thousand mountains) is the name for the karst region of southern central Java that lies to the south east of Yogyakarta, south of Surakarta, and is considered a very dry and poor socio-economical region in Java. It has poor rainfall compared to the volcanic mountain areas to the north and east. Administratively most of the region is part of Gunung Kidul Regency, within the Yogyakarta province besides Wonogiri Regency and Pacitan Regency. In 1993, the world speleologs proposed Sewu Mountains Karst Area as a world heritage. And on December 6, 2004 Sewu Mountains and South Gombong have been announced as eco-karst.
It is a region where archaeological evidence shows very early human activity
It is very popular with cavers. There are 119 caves below of about 40,000 karst cone hills in 13,000 square kilometer area. The only cave-adapted crab from Java, Sesarmoides jacobsoni (Sesarmidae), is endemic to the Gunung Sewu cave system.
On September 19, 2015 UNESCO announced Gunung Sewu area as Global Geopark Network follows Mount Batur area. Gunung Sewu area lays 85 kilometers in 3 provinces, Yogyakarta Province, Central Java Province and East Java Province. The longest cave found at Gunung Sewu area is 25 kilometers Luweng Jaran and the deepest is 200 meters Luweng Ngepoh.
Sewu is an 8th-century Mahayana Buddhist temple located 800 meters north of Prambanan in Central Java. Candi Sewu is actually the second largest Buddhist Temple complex in Indonesia after Borobudur and predates nearby "Loro Jonggrang" temple at Prambanan. Although the complex consists of 249 temples, the name in Javanese translates to 'a thousand temples,' which originated from popular local folklore; The Legend of Loro Jonggrang. The original name of this temple compound is probably Manjusrigrha.
According to the Kelurak inscription (dated from 782 CE) and Manjusrigrha inscription (dated from 792 CE), which was found in 1960, the original name of the temple complex was probably "Manjusri grha" (The House of Manjusri). Manjusri is a Bodhisattva in Mahayana Buddhist teaching symbolizing the "Gentle Glory" of transcendent wisdom (Sanskrit: prajñā). Sewu Temple was built by the end of 8th century at the end of Rakai Panangkaran's reign and completed during the reign his successor King Indra. Rakai Panangkaran (746—780 CE) was famous as a devoted Mahayana Buddhist King that ruled the Medang Mataram Kingdom.