<p>This giant truck travels on a glittering salt road 1,137 feet beneath Detroit, carrying newly-blasted salt several thousand feet to a primary crusher station.</p>
<p>Like a Jules Verne fantasy, a ghostly city with its own network of four lane highways lies deep beneath the industrial heart of Detroit, its crystalline walls glittering and gleaming in the flickering light. It is a world of no night or day.</p>