Hangar One

Hangar One is one of the world's largest freestanding structures, covering 8 acres at Moffett Field near Mountain View, California in the San Francisco Bay Area.

The massive hangar has long been one of the most recognizable landmarks of California's Silicon Valley. It was built in the 1930s as a naval airship hangar for USS Macon and is now part of the NASA Ames Research Center.

Source: Wikipedia