A newly discovered cave deep in the jungles of Vietnam is the largest cave yet discovered in the world. It is 262×262 feet in many places, and is large enough to contain a half-mile New York City block, skyscrapers and all.

The cave, Hang Son Doong, is just one in a network of approximately 150 caves in the Annamite Mountains of central Vietnam. The first explorers to enter the cave traversed 2.8 miles through the underground cavern before rising floodwaters forced them out again. They believe that the passage goes even deeper.

Andy Eavis, of the International Union of Speleology, was the discoverer of the previous record holder, the Deer Cave in Borneo.

“This one in Vietnam is bigger,” admitted Eavis.

Apparently, locals have known about the cave for some time, but have never entered into it’s depths because the noise from the cascading river inside was “intimidating.”

Son Doong actually houses it’s own underground river and a jungle, even cloud formations at times.

Adam Spillane, a member of the expedition, said that an explorer has to be “very close to the cave to find it.” Spillane added, “”Certainly, on previous expeditions, people have passed within a few hundred meters of the entrance without finding it.”

See the pictures of the world record cave at National Geographic