A massive factory spanning over 472 million cubic feet has earned the distinction of being the world’s largest building, surpassing even Disneyland in size. Located in Everett, Washington, the colossal Boeing facility exceeds the Tesla Gigafactory by 33% and has produced over 5,000 wide-bodied aircraft since its establishment in 1967.
Covering 98 acres of land, the mammoth site is larger than the original Disneyland resort in California, which occupies roughly 85 acres. The Boeing plant was created to facilitate the production of the innovative 747 aircraft, a project initiated by then-President and Chairman William M. Allen.
The 747, known as the “jumbo jet,” was significantly larger than any passenger planes in operation at that time. After considering various locations for the facility, Boeing selected a former military airfield just 22 miles from its Seattle headquarters. The construction of the facility, completed in just over 12 months at a cost exceeding $1 billion, required the movement of 4 million cubic yards of earth and the installation of a dedicated railway line for material transportation.
The factory, with dimensions vast enough to house Disneyland, once generated its own microclimate with clouds forming beneath its 90-foot-high roof due to moisture accumulation. However, modern air conditioning systems have since mitigated this phenomenon. Referred to as Boeing’s “best product” by Bonnie Hilory, executive director of the Future of Flight Foundation, the facility has undergone significant expansions over the years to accommodate the production of various Boeing aircraft models.
Currently, the facility employs around 36,000 workers across three shifts, offering diverse roles beyond aircraft manufacturing, such as fire brigade services, banking facilities, childcare centers, medical services, and water treatment facilities. Guided tours of the factory are popular among visitors, with over 239,000 people participating in tours last year.
The facility features an intricate network of underground passages spanning two miles, allowing staff to move between sections without disrupting operations. Ground-level operations include the use of button-activated doors and overhead cranes along 31 miles of rails to maneuver aircraft during assembly.
Boeing anticipates the first 777X delivery to customers by 2027, with a total of 619 orders for both passenger and freighter versions as of November 2025.