This Cave in Vietnam Is So Massive It Has Its Own Clouds and Jungle Inside

Son Doong cave in Vietnam is considered one of the largest caves in the world by volume — its biggest chambers are tall and wide enough to fit an entire multi-story skyscraper inside.

Where the cave's ceiling collapsed in the past, enough sunlight reaches inside to have grown its own underground ecosystem, with trees and vegetation rising in the light pouring through the openings in the rock.

Clouds and local fog can even form inside the cave, because temperature and humidity differences create conditions similar to a small, enclosed microclimate.

The cave wasn't fully documented by scientists and explorers until the 21st century, even though local residents had known about it much earlier — its enormous size and difficult access long made full exploration a challenge.