Berlin, like any other city, has many areas named Mitte, Prenzlauer Berg, ... . Two other ones are Friedrichshain and Kreuzberg, geographically separated by the river Spree. For obscure administrative reasons, Both have been linked together but the inhabitants do not hear this union with the same ear. And the "war" begins. This is symbolic (although ...) but once a year both sides fight (literaly) on the Oberbaumbrücke, one of the most famous bridge in the city. Traffic is stopped, boats are not allowed to sail anymore for the day (the last one who did, remembers that day very well), no metro, no nothing. Both camps meet on the bridge, the police blocks both accesses and the fight can start. It is said that most of the time, Friedrichshain is the winner. People arrived covered of plastic bags, anything they find to protect themselves. Their target is of course the adverse side and their munitions are rotten fruits and vegetables, eggs, water balloons (water ?), one year (I think It was in 2005) some even build a tank in cardboard. It was easy for the other side to burn it ! It all starts with laughs and good humour, It can end with fights and interventions of the police. I can understand, you recall your basics instincts of fighting and It must be a thrill for participants. It was this week-end in Berlin.