Formed in Carboniferous/Permian limestone, the main Sơn Đoòng cave passage is the largest known cave passage in the world by volume – 3.84×10⁷ m³ (1.36×10⁹ cu ft), according to BCRA expedition leader Howard Limbert. It is more than 5 kilometres (3.1 mi) long, 200 metres (660 ft) high and 150 metres (490 ft) wide.
So that’d be nearly triple the volume of the Everett Factory. Though the cave has two holes in its roof, and I don’t know exactly how you define “room” here.
checks
That being said, I don’t know if it is internally divided.
There’s a really large cave in Southeast Asia somewhere.
kagis
The Sơn Đoòng cave in Vietnam:
So that’d be nearly triple the volume of the Everett Factory. Though the cave has two holes in its roof, and I don’t know exactly how you define “room” here.
https://www.youtube.com/watch?v=tOH4gbW18Ts
https://www.youtube.com/watch?v=xVpk7LQML8g
It is sorta internally divided, but there are places where you can see from one end to the other (about a mile).