Another specimen in northeastern Oregon's Malheur National Forest is possibly the largest living organism on Earth by mass, area, and volume – this contiguous specimen covers 3.7 square miles (2,400 acres; 9.6 km2) and is colloquially called the "Humongous fungus".
Uses
The species is considered a choice edible.
Hmmm. Apparently in national forests in Oregon you can harvest up to a gallon of mushrooms for personal use at one time, no permit required, though you're not allowed to sell or barter it.
...that's kind of amazing that anyone can just go out and eat part of the largest organism on earth.
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.
They had to change their venting and airflow system for that building after it formed a cloud and rained inside. When your room can have weather systems, I feel you've entered a whole new category of 'room' by definition.
Factories will win this hands down, especially when you're building large/complex items. It looks like the distinction might be "single building" vs "complex or buildings", but VW's Wolfsburg plant is 70 million square feet. The largest plant I've been to isn't on that list, but it's still over a half mile wide - all under a single roof.
It's actually kind of amazing to see a building with multiple assembly lines of wide body airplanes. The tour is well worth the drive to Everett if you are ever in Seattle.
I went looking but couldn't find a reference. US Air Force Plant 4 in Fort Worth (where the F-35 is assembled) was at one point the longest length building without internal support columns. I've been told that there is a twin building somewhere else, but the one in Texas is 25 feet longer. I just can't find a source with the number!
You could say the Veryovkina Cave in Georgia is the biggest room in the world, if you define a room as a single continuous enclosure not impeded by any barriers or gates. It's referred to as the Mount Everest of caves and has six points of entry once thought to be unrelated. My best friends are cave hobbyists (my body isn't ready as they say, though to be fair neither are theirs for different reasons), seeing/capturing never before things all the time, and are probably evading the law that far below our overworld right now.
Impressively not even close. The Veryovkina Cave is the deepest cave but the largest is the Hang Son Doong cave in Vietnam and that's just under ten kilometers. Again a place shown to not be immune to my friends.
Interesting question. Are we talking about the volume or the floor area? For volume maybe a church? Then St. Peter's Basilica in Vatican City would be the largest. I don't know the layout though, but I assume a large portion of it is the main "room".
Or do stadium with a roof count? Then maybe one of these?
Edit: I don't think I really thought this through. I was thinking too much of more roomy rooms. Most convention centers probably have larger exhibition halls.
Admittedly, The Asylum has a quite a few rooms within it, but I'd say that the antechamber of The Asylum that abuts the outer wall to Outside comprises the majority of the surface of the Earth and its atmosphere, so that's a pretty big room.