Two months in Berlin, and I am still learning how this city works. Some discoveries are about places, some are about people, and others are about the ordinary systems that you very quickly start depending upon when you live somewhere rather than simply visit it. One of those systems is the Berlin U-Bahn. I had used it before, of course, but I was still getting accustomed to travelling through Berlin this way, understanding the lines, recognising station names and gradually developing a mental map of how different parts of the city connect. This morning I took a few photographs along the way. Looking at them afterwards, I realised that they recorded something else as well: how different the reality of Berlin's underground railway was from the image I had somehow created in my mind before moving here. It was not the nightmare I had imagined. Just walk into the station One of the first things that struck me about Berlin's u...