Gunung Sewu Geopark represents a mountain range stretching from the center of Java to the east of the island.
These mountains show unique karst features at the surface (exokarst) and underground (endokarst).
At the surface, this unique karst phenomenon is expressed by the presence of more than 40,000 cone-shaped hills (Sewu means "a thousand" in Javanese).
Underground, the karst phenomenon appears as 119 caves with stalactites, stalagmites, and underground rivers. Early human fossils dating back 1.8 million years have also been found in the caves.
Note: The object illustrated in this article is part of the author's private collection.