This is a video by National Geographic's photographer Carsten Peter who ventured into the largest cave system, yet known to man, on earth. The cave - called 'Hang Son Doong" - is located in Phong Nha-Kẻ Bàng National Park, Bố Trạch district, Quảng Bình Province of Vietnam. Located near the Laos-Vietnam border (17°27'25.88"N 106°17'15.36"E) the cave has a large fast-flowing underground river inside. There’s also a jungle inside this mammoth cavern and a skyscraper could fit in it too. The cave's end is out of sight but, it houses life forms that have yet to be documented and it houses waterfalls of its own.

During the Vietnam War, North Vietnamese soldiers hid in caves from U.S. air strikes. Bomb craters, from the war. now serve as fishponds.

Son Doong cave is 5 times larger than the Phong Nha cave, previously considered the biggest cave in Vietnam. The biggest chamber of Sơn Đoòng is more than 5 kilometers long, 200 meters high, and 150 meters wide. With these dimensions, Sơn Đoòng overtakes Deer Cave in Malaysia to take the title of the world's largest cave.

To view still pictures of the inside of this cave, please visit: http://ngm.nationalgeographic.com/2011/01/largest-cave/peter-photography