Inside NASA’s historic Vehicle Assembly Building (VAB) at Kennedy Space Center, towering steel gantries and massive cranes dominate the cavernous interior. This is one of the largest single-story buildings in the world, designed in the 1960s to stack the Saturn V rockets of the Apollo program and now used for assembling the Space Launch System (SLS) for the Artemis missions. The central high-bay area, seen here from above, includes multiple platforms and access decks allowing engineers to integrate and inspect rocket stages with millimeter precision. The structure’s immense scale—capable of accommodating vehicles over 500 feet tall—remains a defining symbol of America’s spaceflight engineering capability.