How about Boeing Everett factory?

Boeing's factory is really big-imagine that dozens of planes are assembled in it at the same time. Can it not be huge? The factory building is a huge matchbox from underground to the ground. There are various assembly workshops here, as well as staff offices, conference rooms, cafes and restaurants. It is particularly worth mentioning that there are 30,000 employees working around the clock in the Boeing factory, but they can't hear any noise when they walk in. It really surprised me.