[2] These mountains are a unique karstic landscape, characterized by the phenomenon being present on the surface (eksokarst) and subsurface (endokarst).

Because of the uniqueness of its ecosystem, the 1993 International Union of Speleology proposed the Karst Area of the Sewu Mountains to be classed as a natural world heritage site.

[6] Nglanggeran primeval volcano in the Patuk area is only 600 meters high but there are excellent views from the peak to the north towards Mount Merapi and to the south across to the coast of Java.

[7] Siung Beach Bay is about 300 meters length, but swimming is prohibited because of dangerous rocks and severe waves.

[8] 200 meters east of Siung Beach there is a 10-meter Jogan tiered fall in Tepus district which is 70 kilometers from Yogyakarta (2 hours drive).