Jomblang Cave

Jomblang is a collapse doline in the karst of Gunungkidul, in the Yogyakarta region of Java: thousands of years ago the ground gave way and dropped, forest and all, into the cave below. What remains is a vertical shaft about 50 metres wide at the mouth, known in Javanese as a luweng, with ancient vegetation growing at its bottom. The local community manages it as a site for conservation and small-group adventure tourism.

Visitors go down the way cavers do: on ropes, lowered more than 50 metres into the shaft with the operators' vertical-caving gear. From the bottom a sloping passage leads about 270 metres to the foot of a second opening, Luweng Grubug, where the roof lies about 90 metres overhead. Around midday on a bright day, sunlight falls through that opening in a single column, strikes a mound of flowstone and lights the drifting mist and dripping water around it. Locals call it cahaya surga, the "light of heaven". The beam usually appears only between about 11 a.m. and noon, so descents are timed for it. Photographers come specifically for it.

The descent is a real undertaking rather than a stroll, and the light depends on the weather. There is also a darker local memory: folk accounts say the shaft was used to dispose of the bodies of people accused of Communist ties. The site is in Pacarejo village, Semanu district, about 14 km from Java's south coast.

Getting there

The cave is about 8 km from Wonosari, the main town of Gunungkidul. Adisutjipto Airport (JOG) in Yogyakarta is about 35 km away as the crow flies, and the last stretch is by car on rural roads. Access is only as part of an organised descent with the local operators, whose ropes and harnesses are used by every group.