The 60-metre high exhaust stack for the supply and removal of air from the B 96 road tunnel and the car park decks is the tallest structure at Berlin Hauptbahnhof. The subterranean section – approximately 20 metres below ground level – was erected as a reinforced concrete structure, on which stands a 60-metre high steel structure built of 250 tons of steel. The individual bays are fitted with 27,000 glass blocks. The Deutsche Bahn logo on each of the three sides of the exhaust stack can be clearly seen across a wide area of the centre of Berlin. The lighting installed inside the exhaust stack shows off the design of the tower to great effect.