For most of the past decade, though, it was a haunt rather than a landmark – a hulking steel skeleton and reminder of engineering ambition looming over Silicon Valley. That changed last month. On March 20, officials and community members gathered inside the fully restored hangar to mark a moment many had stopped believing would ever come.

Of fog and airships

Hangar One is among the world's largest freestanding structures, covering eight acres at Moffett Field near Mountain View. Eight football fields could fit inside its cavernous interior, where fog sometimes gathers near its 198-ft (60-m) high ceiling. It measures 1,133 ft (345 m) long and 308 ft (94 m) wide.