I just know that there is an extraordinary beautiful cave from an International Amazing Race. What a shame, I’m an Indonesian, but I don’t know even a bit!
It is a vertical cave located in Semanu, Wonosari, about 50km south east of Jogjakarta, Central Java. This vertical cave that has trees grow from its bottom is connected to another cave called Grubug, a horizontal one which also has a stunning view with its tube underground river.
This river is known as Kalisuci, or Holy River. You can reach both of these caves either through Grubug, the horizontal one, or Jomblang, by sliding down using a rope.
At noon, it will gives you enough ray until you reach the bottom, indeed you still need to bring your own torch to give you enough light to reach another side which is in Grubug, and probably an inflatable tire, so you can float in the Kalisuci, the underground river that is 15m under the cave.