Entrance lobbies are bottlenecks through which employees,board members and visitors all throng before entering the heart of a company. Entrances also leave an initial,lasting impression. How is a company's self-image reflected in the construction of its entrance halls? In our series Dax Portals we look at the foyers of Germany's 30 DAX listed companies. The Post Tower in Bonn is a monument made out of glass. A symbol of transparency? A sign of openness? Phillipp Bilsky takes a look behind the facade.