All this is my sorry excuse for not researching something I had planned to do in Berlin, namely track down the Reichsluftfahrtministerium. It was the headquarters of Hermann Göring's Aviation Ministry and for some reason survived Allied bombings and Russian artillery during World War 2. That is, it's the only remaining major Nazi-era building in the city -- a real curiosity. (Background information can be found here.)
I had a free day to rattle around Berlin, visiting places I'd seen before and looking for new buildings, stores and such things that comprise a thriving city. Towards the end of the day I suddenly remembered that it would be nice to track down the Reichsluftfahrtministerium. Except I didn't know where it was other than it probably would have been near the Wilhelm Strasse, the avenue where ministries had tended to be since the Kaiser's day.