Mount Sewu Geopark stretches across three districts, namely Gunungkidul, Wonogiri, and Pacitan, as well as in three provinces, DI Yogyakarta, Central Java and East Java. This line of limestone karst beauty has been known to the world since the 1800s. Not only its natural beauty, this Gunung Sewu Geopark has the archaeological wealth of past human cultures.
A dozen thousand years ago there was a prehistoric human paleolithic culture known in Southeast Asia with the Pacitanian Culture. A total of 33 natural heritage sites are scattered in Gunung Kidul (13 geosite), Wonogiri (7 geosite), and Pacitan (13 geosite). This Geopark has been recognized as a national geopark since 2011 and has been recognized as UGG since 2015. Lake Segara Anak is seen from the summit of Mount Rinjani at an altitude of 3,726 m. Rinjani is part of Mount Samalas which erupted to paralyze the world in 1257.
This mountain range has a very unique karst landscape, it is characterized by the presence of phenomena (exokarst) and subsurface (endokarst). Surface phenomena include positive formations, such as karst hills which number ± 40,000 cone-shaped hills. The negative form is karst valleys and karst lake.
Subterranean phenomena include karst caves which number no less than 119 caves that have stalactites and stalagmites, and all underground streams. Because of its unique ecosystem, then in 1993 the International Union of Speleology proposed that the Karst Mountains of the Sewu Mountains enter into one of the world’s natural heritage. In these caves were also found ancient human bone fossils from the old stone age about 1.8 million years ago along with stone tools for hunting.
Note: Karst is a form of the earth’s surface which is generally characterized by the presence of closed depression, surface drainage, and cave. This area is formed mainly by dissolving rocks, mostly limestone.