That isn't really flat, but mostly downsloped for the first half, even if only slightly. I know it sounds unreasonable, because people then didn't believe me either.

Except when they've seen me doing it.

Edit: I also caught fire for being unimpressed with Tour de France and the likes, at the times.

Edit: Also klicking that link it seems to be a different route now, which would be a detour almost to the Airport of Cologne. (Sigh). The route I took was more direct, about 55km.