Dusseldorf?

Go for it. And do visit Benrath and/or Dyck castle. Do an image search on bing or google entering "Schloss Benrath" or "Schloss Dyck"...

I spent an evening in Düsseldorf years ago. The old town is interesting and we had dinner at a nice restaurant/brewery there. I don't know if there is enough there for a full day, but the website for Düsseldorf (in English) is here. Note, you will have much more luck finding information about it if you use the correct spelling, Düsseldorf, or Duesseldorf if you can't make Umlauts.

Thanks, the website will help. I was also thinking of Cologne because of the cathedral. Everything else was destroyed.

Both Cologne and Duesseldorf have plenty to do and see to keep one busy. Unfortunately, they do not get much attention in the guide books.

Allow me to make a comment about all of Cologne being destroyed in the war. Like many other cities, Frankfurt included, bombing was heavy and much was destroyed. Often, the main parts of the buildings and houses were intact. The photos just look bad, After repairing water and electric, etc. and a new roof, they were quickly usable again. Go down some side streets in Cologne and you will quickly see that the city was not "destroyed" in the sense that one often thinks. There are gorgeous neighborhoods there, lots of unique stores, cafes, parks, there is so much more to Cologne than just the cathedral.

They also have some great museums in both cities.

Thanks for the tips. Often websites don't really tell the whole story. My goal is really just to walk around, see some landmarks and visit a museum or two. I know I won't get to know a city at all, but want to get the flavor of it. I live in Amsterdam several months a year and still learn new things every time I come.

I haven't been to Dusseldorf, but have been to Cologne on three different. The last time I was there for three nights and found many new places to visit.

We visit Koeln/Koln(plus umlaut over o/Cologne regularly and think it's a great place to visit in the area.

I also really like Bonn, which isn't far from Koln.