Berlin's House-Numbering System
Frederik William III. has his merits: The Prussian king founded the University of Berlin and pushed some reforms promoting freedom and equality. But in 1799 he had a weak moment when he invented the Prussian house-numbering system which still exists in Berlin. His idea was that, relative to the position of the City Palace*, the numbers count up on the right side of the street: 1,2,3,4,5 ... Quite simple, but at someplace the street ends and the numbers now continue to count up all the way back on the left.
According to Murphy's law, this u-numbering system will confuse you the most, the more important punctuality gets.
Say, you have a job interview at 10 a.m. in 171 XY-Strasse and the first number you see when you arrive at said street is number 53. You hasten up the street until it ends at a crossroads - and with number 85. The number of the house on the other side of the street reads 86. Familiar with the zigzag-system (even numbers on the left, uneven numbers on the right) you think that's o.k. So you cross the crossroads to find AB-Strasse. Now that's odd, where is 171 XY-Strasse? Answer: At the opposite end of XY-Strasse, opposing house No. 1 - you walked down the street on the wrong side and in the wrong direction. Be glad when you only arrive 10 minutes late for your interview.
Actually, this system fits the proverbial Prussian sense of orderliness well. It works like double-entry bookkeeping: When one account is being debited, another account is being credited, with the debits of each transaction equal to the credits it creates.
In our example, we have number 1 on the right hand side at one end of the street and number 171 on the other side of the street. That sums up to 172. Had we crossed the street when we first saw number 53, we would have found number 119. 53 + 119 = 172. You get the idea. And yes, I know, 85 + 86 is not quite exactly 172, but I did say the house-numbering system can be a bit confusing, didn't I?
(continues below) Now to make matters worse, Berlin has grown, well: somewhat, since 1799, and as you can imagine, extending a street can get difficult when using the u-numbering system. Hence, it can happen that you go down XY-Strasse and, without further notice, you are all of a sudden in GH-Strasse. Those responsible then thought, inventing a new street name was easier than to force 2,045 residents and shop owners to change their business cards and newspaper subscriptions.
You may feel lucky to have the zigzag-system in your hometown. But as I wrote someplace else, Berlin has something for everyone. We even have the zigzag-numbering system, you are so familiar with. Sometimes and someplace. Most often, however, when you thought you just got used to the u-system.
What, two different systems don't make it easier? Now you are difficult to please.
At least, you now know what to do when your taxi driver stops at number 15, not 150 as you requested. No need to issue a fatwa against Berlin's notoriously rude taxi drivers. Just remember Frederik William III. - and cross the street. And a last tip: Google Earth can cope with both systems fairly well.
* Yes, that's the thing that was partially destroyed by WWII, completely destroyed by the socialists, replaced by the Palace of the Republic (or Erich's Lamp Shop, with "Erich" standing for Erich Honecker, head of GDR's government for a couple of decades), and which is going to be rebuild. It's probably going to be No. 1 Soandso-Street, but who knows.