My second weekend after starting work in Hannover took me to Köln, or as English-speakers more commonly refer to it as, Cologne. If you are trying to learn the language in this country and there is one word you don't bother learning, it's "Köln". Saying "Cologne" tells them you speak English, but trying and failing to say "Köln" tells them you're an arrogant tourist that thinks they know everything. If you do still want to try, to execute the proper pronunciation you must imagine you are gagging on food at the same time as you are coughing. That's how you say "Köln".
The city is most famous for its gargantuan Gothic cathedral, or Kölner Dom, which is literally the first thing you see when you enter the city by train.
Everything radiates out from the Dom, and it is the "unofficial symbol of the city" as per wikipedia, and my own observations:
Note the beer (the local variety is known as Kölsch, same rules for pronunciation apply) with the cathedral on it. Even better was the nun I caught drinking. Not really relevant to the city, but I have to share.
So the city itself was a Roman colony, and the name eventually went from "Colonia" to "cough-gag". There's still a couple of things remaining from the Roman city, the coolest of which I found was the Praetorium, which was excavated underneath the old city hall. I don't think the Romans had neon green and purple lights, but I don't know my history that well.
Then, with the rise of the Holy Roman Empire, the city became a partially independent city-state in the Medieval ages, complete with moat and drawbridges.
Nowadays the city is full of modern architecture too, for better or for worse. Like most of Germany, it was mostly flattened during the war, and most of what remains is new or was deliberately rebuilt in the old style, like the multiple Romanesque churches around town.
Oh yeah, churches. You can't walk more than 5 minutes without coming across one, and the title "Holy Cologne" is well deserved.
Lastly, I know you're wondering it, and yes, Cologne was invented in Cologne. The problem is, no one flies planes like the Wright Brothers' anymore, or uses the Alexander Graham Bell telephone. Eau de Cologne smells like crap. Apparently it is what senior citizens in Germany use. But boy does it look pretty in those teal bottles!