I'm gonna spend one day in Hamburg and one in Koln, that's not too much time...
So, considering the short time, can anyone tell me what is there really worth seeing?
I mean, not night life or restaurants and things like that, but something significant, something unique perhaps?
For example one thing that I will definitely visit in Koln is the "Cologne Cathedral", an extraordinary building that always fascinated me, and now is my chance to actually see it.
I know that Hamburg is one beautiful city and there is plenty to see there and I already found something to my (maybe dubious?) taste: Miniatur Wunderland "The world's largest model railway museum" Yeah, don't laugh, I like toy trains

Yeah, I know about Wikipedia and travel guides and such, (I once read a travel guide about my city and was almost nothing there that I would recommend visiting.) but I prefer to hear some real people opinions.