This is the sacred site in Central Java at the south coast that I will visit on my next trip. Goa Langse is situated under a 400m steep cliff east of Parangtritis. The vertical cliff have many wooden and metal ladders to help in the journey. It looks very dangerous but many people had been there. In the photos, you can see the amazing landscape and vista.
Here is a link to youtube video of the cave. Just cut and paste to google.