A pioneering office building for the 21st century in form, technology and ecological orientation, that is the 2002 completed Post Tower. The 162.5 meter high glass tower overlooking the Rhine is the tallest building in North Rhine-Westphalia. Despite its height, its slender shape makes it appear filigree and fits well into the landscape. The post tower consists of two halves. The northern and southern half ellipses are separated by a 7.20 meter wide space. A steel-glass construction connects the two halves. The glass facade also ensures a high proportion of natural sunlight inside. Twelve high-speed elevators bring employees and visitors to the 40 floors. When constructing the Post Tower, the client Deutsche Post DHL Group emphasized two things in architecture: the comfort of around 2,000 workplaces and low energy consumption. Sophisticated air conditioning technology ensures that the Post Tower does not require complex air conditioning with high energy consumption. The double shell made of glass is used for this purpose. The air exchange takes place through the small ventilation flaps in the double-walled outer facade and is adjusted depending on the outside temperature. "The tower breathes in the wind," says Helmut Jahn, the architect of the Post Tower. This means that 30 percent less energy is needed in the tower than in comparable buildings. Source DHL