The northern limitation of the Autostadt Wolfsburg is created by a long, rectangular water basin with two glass cylinders to the northeast: the AutoTürme. They all symbolize the process of vehicle production and serve as an intermediate storage for the newly completed cars prior to delivery. Every tower holds 400 vehicles which are transported via elevators into the free shafts of the 20 storeys. Every 40 seconds a new car arrives underground at the cylinder from the production plant, while another leaves the towers in the direction of the KundenCentre. This constant movement to the inside of the cylinder as a glass motor sets the heartbeat of the Autostadt Wolfsburg.