You stumble upon a rusty old bunker, once used by the US for Minute-Man launches, a rare sight. You enter the bunker. It's weirdly deserted and you enter. But instead of finding a missile silo you find an airlock. You enter and make your way past it. And suddenly you find yourself in a ginormous factory floor. Machinery moving about. Robots whizzing by. And the factory itself seemed to constantly be moving or changing as if it was alive!