The Very Large Structure is a concept for a 600-foot tall city on treads weighing over 300,000 tons.
The Very Large Structure (VLS) is described as a 600-ft-tall "city on wheels" that would remain in almost constant motion as it rolled over the countryside. Consisting of a massive superstructure on a 1,700-ft-long platform born along by massive tank-style treads, the VLS would concentrate all of the activities and resource consumption of a city into a single mobile structure.