Remember how Elon Musk casually mentioned that Tesla had built a new assembly line in just three weeks to help it meet its lofty Model 3 production goals? It was more audacious than you might have thought. A combination of follow-up tweets from Musk, first-hand observations and Fremont's own approval process has made clear that Tesla built new manufacturing inside a group of several giant tents (or rather, tent-like Sprung structures) to boost output of its high-volume EV. If you think that sounds audacious, you'd be right. Ars Technica learned that each 'tent' is 150 feet long and 53 feet high, and there's no known instance of other car manufacturers doing this before.