It just so happens that the Berlin Marathon will be taking place during my September stay in Berlin. I know the marathon is huge with perhaps a million spectators. (And interestingly, the marathon will be taking place on the same Sunday as the national elections this year.)
To those who have been in Berlin for or during the Marathon event, just how difficult will movement in the city be on race day? How crowded will the city be that weekend? And any suggestions for what to do or avoid doing during that weekend?