Every day, hundreds of people walk past a green door in the Gesundbrunnen Underground railway station unaware that within lies a subterranean labyrinth full of authentic history waiting to be experienced. How uncomfortable it must have been during WWII to be crammed inside these small chambers – the depleted air supply, the incessant clanging of ventilation machines, the thundering of bomber aircrafts overhead. This atmosphere of fear and anguish can still be sensed today. Berliner Unterwelten e.V. | Tour 1 click on panorama image icon, when pic appears, after a few secs, then hold left mouse button down, and drag across pic to view 360 degree l/r up/down .. tour 2 as well, but only 2 pics. well good..