My friend and I are traveling to cologne for five days on the 31st October, and are going to a concert at the cologne stadium on a Sunday night. Obviously it will be late finishing, so we are wondering as to what transport we could take back to our hotel in the city centre, if there's anything still open? If not, are is there a taxi system, and would it be expensive? I am almost fluent in German so it wouldn't be a big problem.. you can probably tell we're only from a small town, not familiar with the transportation systems in cities! Any advice would be appreciated, thank you!!