Caves don’t give up their secrets easily. Lack of light, treacherous passageways, and their knack for remaining hidden make them some of the least explored places on earth. However, the risk and inconvenience often results in stunning experiences as with the Glowworm Caves in New Zealand or Mexico’s Cave of Crystals.
Part of the world's largest archipelago, Java is one of the best places to explore if you have a hankering to get underground. The southern part of the island is covered in limestone hills which are believed to contain hundreds of caves. One of the most impressive is the Jomblang complex which treats its visitors to an enormous sinkhole, a subterranean forest and a sparkling light display for a few hours a day.
The Cave of "Heavenly Light"
Indonesian newspapers and tour agencies call Jomblang the cave of "heavenly light" and with good reason. Seeing it isn't the easiest endeavor, however. The complex is located on the outskirts of Yogyakarta, which is the island’s artistic and intellectual epicenter. After a 90-minute trip through the bumpy backroads, you’ll arrive at an area once covered in a vast expanse of teak trees. Deforestation has stripped the region of some of its past glory, but the cover is still thick enough that the sinkhole isn’t as visible as you'd like a 50-meter gap in the ground to be.
The only way to enter the complex is by rappelling. Those brave enough to entrust their life to a harness and rope quickly find themselves at the bottom of the sinkhole in the middle of an ancient forest. The roof of the cave is thought to have collapsed thousands of years ago and since then a collection of plants, many on the verge of extinction, have had the chance to flourish and weld there way around the entrance Jumanji style. The first cave (Jomblang) connects to a second (Grubug) by a 300-meter corridor. The quarter-mile trudge through the muddy passageway in complete darkness isn't pleasant, but when you enter Grubug, the darkness dissipates and leaves you standing in a pool of light. Enjoy the view. It only lasts an hour or so before the sun continues its predictable course across the sky.
How to Do It
The most convenient way to see Jomblong Cave is with Viator or Your Jogja. Both offer full day tours which include pick-up and drop off and experienced guides to provide you with the proper equipment and assistance in rappelling down the sinkhole. Those who are confident in their canyoneering can rent a car and make their way down the sinkhole on their own or go straight through the top of Grubug.