On my third day cycling the Berlin wall trail (which is a circular route of about 180km around the former border of West Berlin, in case I didn't mention it before), I came to the south-west of the city, in the area around Potsdam, home of the kaisers, a place of lakes and forests and very many castles and palaces. Potsdam is where Churchill, Truman and Stalin settled the post-war division of Germany and then became the headquarters of the Russian presence in East Germany. It still has a strong whiff of the Cold War about it. I crossed the Glienicke bridge, which was used for spy exhanges, then passed the former KGB prison below, which is being turned into a museum. Later I passed some 19th C barracks buildings that were occupied by red army troops after the war and vacated by them only in 1994. They are locked up and awaiting conversion into luxury flats, but I found a way into one of the buildings and discovered lots of Russian graffiti left by the soldiers.