I wasn't that impressed with Cologne, probably because it's so modern, given how it was nearly leveled in WWII and I had just come from Heidelberg, which was largely spared Allied bombing during the war, so it retained its baroque charm of narrow cobblestone streets and beautiful old houses. I also had a fantastic meal at a 400 year old German restaurant, Schnookeloch, where they appear to have perfected wienerschnitzel and potatoes (and beer). But to be fair I only spent about 8 hours exploring each city, so my impressions were limited.