Son Doong is the world’s largest cave and is found in Vietnam, in the central Quang Binh Province. And last Sunday, a group of Japanese filmmakers went to the area to shoot a 3D documentary about the world’s biggest cave.

According to a member of the Kyodo news agency, the 12-man crew who will be filming the cave, it will be the first-ever 3D documentary about caves in the world. The film will feature the different organisms and creatures inside the cave as well as the surrounding forests. 

According to reports and legends as well, the cave was first discovered by a local resident named Ho Khanh in 1991. But he forgot the entrance. Official records thus name the British Cave Research Association as the official founder, who discovered the cave in 2009 when a caver team discovered Son Doong Cave at the UNESCO-recognized world heritage site Phong Nha-Ke Bang National Park near the Laos-Vietnam border.

But Khanh, who first found the cave, is appointed as the guide, while the association will accompany the film crew during this pioneering endeavor.

Son Doong Cave measures 200 meters high and 150 meters wide at its largest. This size is almost double the former world’s largest cave, the Deer Cave, in Malaysia, measuring only 100 meters high and 90 meters wide compared to Vietnam’s cave.

Like hitting two birds in one stone, the Japanese film crew also discovered another cave during its expedition.