Köln

https://community.ricksteves.com/travel-forum/germany/can-i-see-enough-of-cologne

I'm a big fan of Cologne. Note that you should not "skip" the Medieval Art and the Ethnographic museums (assuming they appeal to you) just because they are among the few Cologne attractions that require the U-Bahn. (The Botanical Garden is another). If you have a day-ticket for U-Bahn anyway, and you like art, you might seek out the (obscurely located in a modern shopping mall) rare Käthe Kollwitz Museum. (Big current show at MoMA in NYC.) This would also relate to the many posters here interested in the two World Wars.

It's a long walk, but we enjoyed crossing the river on one bridge, and returning by another. You might want to make a daytrip to Düsseldorf, and even on to Wuppertal. I have an idea it's easier to bus from Düsseldorf or Aachen, but Monschau is a very charming (if over-visited) Fachwerke landmark town. It's much "purer" than the Fachwerke districts embedded in now modern cities. If you have the time, Aachen is worth a full day. I suppose the Aachen Cathedral tour requires pre-booking?

Edit: The only, single, negative item I will confirm is that the "old town" section is quite modern/restored and missable. But right beside it are Roman and Jewish Quarter archaeological excavations, including a medieval mikveh which (when I was there) you could leave your passport in exchange for the key, to visit on your own!

I didn't mention that as a NYC resident, I often see J.M.W. Turner's 1826 painting of the Cologne river port. (Frick Collection) I took a postcard of it to try and find his viewpoint along the river, but didn't quite get there. I suspect the waterline has moved over the years.

The cathedral, a stroll around the town, see the cathedral at night, get up early and visit some place else. It isn't a bad place to visit, but to me it was a day visit and an evening. Five days in Cologne is a long time and I have to say I did not take any day trips because I was there for such a short time in that area. Unless you have to be in Cologne for 5 days I would consider heading south to the Koblenz area and south on the Rhine to some village visits.

Just know that outside of the Cathedral and the chocolate factory - it is a very underwhelming town (except at Xmas for the Xmas Market). It was mostly destroyed in WW2 and rebuilt in the 50s, so it is not a pretty quaint German town like so many other options you could have. Is there a reason you chose Cologne? There are so many other German towns that are like they were centuries ago. I'd stay somewhere else and do a day trip to Cologne if it's important to you. Personally, I'd choose another area if flights aren't booked. We've been many times, most recently 5 weeks ago - we were there for one day on a Rhine River Cruise. While it is nice, it was our least favorite stop on our 14 day river cruise.

They do have a small documentation center - in the basement you can see where the prisoners lived.

Aachen is a nice close by town with a beautiful cathedral. BUT . . . that's about it for places nearby worthwhile.

Like Tim, I loved Cologne, which is a beautiful city with a lot of ambience and the most gorgeous cathedral you will ever see. There are a number of good restaurants and also has some fun shopping as well. One restaurant I recommend is maiBeck FÜR DICH, which had some of the best food I ate in Germany. I also ate at Brauhaus früh am Dom, which serves authentic German food. I opted for beer and sauerbraten, and it was very tasty. Both restaurants were within walking distance of the cathedral.

Since you're staying for a bit, that will give you time to explore Cologne and all of it sights, but will also give you time for a day trip to Aachen, which is a quick 30 minute train ride away, and well worth a visit. Its cathedral is quite beautiful (especially the interior, which is drop-dead gorgeous) and houses the remains of Charlemagne, leader of the Holy Roman Empire. The town is also very charming and has a lovely vibe to it. It's smaller than Cologne and you could easily spend some time just walking around and enjoying the sites. Don't miss the Granus tower, which is next to the Rathaus (town hall) and is one of the few pieces remaining from Charlemagne’s palace. It dates back to the 8th century, making it over 1200 years old.

I too am fond of Cologne. Papa Joes Biersalon in the Altermarkt for its unique collection of antique music machines and animatronic juke box, Tuenes and Schael. These characters were 19th century puppet characters and Cologne's own Laurel and Hardy.

many years ago I lived on the Aachenerstrasse just out of the centre of town for 3 months. Not once did I find it boring.

Cologne is a fun city to walk around in. For those who think the whole city was destroyed, you have never walked around the Belgian Quarter. Beautiful parks, lots of museums, great pedestrian shopping, a fun Alt Stadt. and lots of Roman history.
It surely is more than a one trick pony.

I'm an American that has been living in Cologne for over 12 years. I do understand how many find the city underwhelming as a tourist. But the motto here is 'Cologne is a feeling'. She isn't the prettiest, but the people, and the history, make the city unique compared to other cities in Germany.

All the guide books can show you the main sites; of which there aren't many at the moment. Unfortunately, the city is in the middle of building a Roman History Walk through the center of Cologne. As a result, there is a lot of construction and many of the Roman museums/sites that make Cologne famous are closed, including the Roman Germany Museum right by the Cathedral. The 'replacement' museum they've set up across town is not worth the 6euros.

Definitely visit the Dom, and either read up about it or take a tour. The Dom Forum organizes tours of the cathedral, some in English. Go to the website, or walk in on the day (although English tours might be booked up, depending on the time of year). They also offer a rooftop tour that is really special. This one sells out very early and needs to be booked in advance, but you get to walk along to top of the Cathedral and see the workshop up there.

If you are here at Christmas market time, or at Karneval, there is nothing else you need to do but these things.

With 5 days you have plenty of time for day trips. Not sure if you're headed south into the wine country at some point, but I always take my visitors down along the Rhine. This is the best representation of what visitors have in their head when they think of Germany. During the high season the KB boats run a sort of hop on hop off service, so you can decide where to go. We always take a train from Cologne main station to Boppard. Boppard is very small, but cute, and the KD boat stops here. The Rhine doesn't get really pretty until after Koblenz, so take a train to save time. From Boppard take the boat down the Rhine and get off where you like. I like Bacarach (small but charming) or Rüdescheim (bigger and many more cruise ship tourists, but for a reason). If you've spent the day getting to Rüdescheim, have dinner and then take the train back to Cologne. It's a long day, but doable and worth it! If you have the time, spend a night someone along the Rhine. Warning, the smaller towns are totally dead after 10p.

After that, spend time in the famous breweries in Cologne. My favorite is Gaffel am Dom, right by the train station; you'll probably need a reservation which can be made online. People are quite friendly here and it's easy to strike up a conversation in a beer hall. Drink Kölsch and eat the hearty German food.

Cologne loves to party. Depending on when you're here, there are festivals almost all the time over summer. Find an event calendar and see what is happening when you're here.

If you are a history person (I'm a Roman nerd), it is possible to see Roman ruins throughout the city. Cologne was the northernmost capital of the empire and there are always ruins being discovered, even now. It's possible also to walk the Roman wall that once rounded the city; but you need a guidebook. After the Romans, the city expanded further; you can also see some of the gates from this wall. Additionally there are 12 Romanesque churches from the Middle Ages that worth looking at. Of course not all are original from this time, as Cologne was 95% destroyed during WWII. The Dom Forum also coordinates walking tours of these churches; although not sure now many are in English.

Cologne is a great city! It's not huge, so enjoy the smaller, intimate feel. And the people are generally friendly and helpful. Have fun!

I am surprised nobody has yet suggested the basilica of St. Ursula and the Golden Chamber, which is decorated (yes, decorated) with human bones. A short walk from the Dom, this little church seems unremarkable, but the bone chapel is stunning, fascinating, a tiny bit macabre, curious, and absolutely worth seeing. It's tucked into a corner of the church and easy to miss. So worth such a short walk!