The Saturn V rocket, which carried the first men to land on the moon, was as tall as a 35-story building. This rocket was built inside an assembly building so big that it could fit several of these huge rockets in an upright position!
This structure, called the Vertical Assembly Building, or the VAB, is at Cape Canaveral, Florida. It covers ten acres, almost nine football fields, and stands as high as a 50-story building, making the VAB the most spacious building ever constructed!
When the rockets were finished, they were moved out of the VAB through doors that were 460 feet high, the largest doors ever built!