Well ... Cologne and its Cathedral. I'm living in a small town close to Cologne, around a 30 minutes drive away and so I go there quite often for shopping, clubbing or for meeting my penpals who usually visit Cologne and/or Berlin when they're in Germany. The cathedral is amazing and you actually can't miss it as it's "just there". A guided tour is always a plus when you're there, 'cause then you at least forget about people who don't pay respect to a religious building. I'm Catholic, but not religious and don't care much about the Pope and the Roman Catholic Church, but I think that we shall pay respect to religious buildings as many people are religious and their feelings shouldn't be hurt. Well, let me go on with the cathedral: if you're there you also should climb up the many steps to the cathedrals "tower" from where you have a great view over the town. Also the treasure chambery with the coffin of the "3 Holy Kings" and many interesting religious items should be visited. Besides the cathedral Cologne has to offer much more, like interesting museums (including a chocolate museum), many other worth-to-be-seen churches and a few Roman remains as well as cultural experiences like the famous carnival (in February) and Europe's biggest GayPride Parade (= Christopher Street Day, in July).