GREAT NATURE -- The Secret Mountain: Papua New Guinea

Synopsis
On New Britain Island in Papua New Guinea in the South Pacific, is one of the most unique, unspoiled jungles in the world. Although it's been extremely difficult for research teams to go into this jungle until now, new explorations have begun to paint an overall picture of the jungle floor. Viewed from both the sky and on the ground, a gigantic waterfall, a vast opening in the ground, and a huge amount of water flowing in a massive underground river are revealed. This program attempts to find the source of this river based on an unfinished map created by a French research team 30 years ago.