A colossal factory in Everett, Washington, spanning over 472 million cubic feet, holds the record as the world's largest building and even has its own microclimate. The Boeing facility, which cost £745 million to build, overshadows its nearest rival, the Tesla Gigafactory, by 33%. It has produced more than 5,000 wide-bodied aircraft since opening in 1967.
The site covers 98 acres, making it larger than the original Disneyland resort in Anaheim, California, which occupies approximately 85 acres. The plant was built to manufacture the revolutionary 747 jumbo jet, which was roughly two-and-a-half times the size of the largest passenger aircraft at the time. Construction took just over 12 months and involved shifting 4 million cubic yards of earth, requiring a specially constructed railway line.
In its early days, clouds would form beneath its 90ft-high roof due to moisture build-up, but modern air conditioning has eliminated this phenomenon. The factory has undergone two major expansions: in 1978 for the Boeing 767 and in 1992 for the Boeing 777. Additional buildings have been added for robotic assembly of the 777's fuselage and manufacturing of the composite wing for the 777X.
Approximately 36,000 employees work at the site daily, including staff for its own fire service, banking, childcare, medical centre, and water treatment plant. The factory also employs tour guides; in 2024, 239,579 visitors paid £31 each for a tour. Visitors can see the production floor, while employees use over two miles of underground tunnels and over a thousand bicycles to navigate the site.
