Cologne was not one of the "top ten" cities of the Roman empire, but this museum deserves to be among the top ten museums of Roman archeology for the way it brings the Roman city back to life. The city had great military importance since it controlled the important permanent bridge over the Rhine river (leading to today's town of Deutz, which was a frontier fortress). Some of the huge stakes of this bridge can be seen in the museum today.
The exhibits are arranged thematically, from the basement, where the Dionysus-mosaic appears where it was found during the Second World War. You get a better view from the upper floors. It conforms to a standard type of Roman floor mosaic, of which there are many examples all over the Roman world. Compared with those in Tunisia or Turkey, it is of a lesser artistic merit -- not surprising since the top artists of the time would not have travel to the end of the Roman world, which Cologne was! But clearly their pupils and patterns did.
One thing I took away from the exhibits is the striking mobility in the Roman world: A river pilot's tomb stone proudly declares that he was from Alexandria. And most the cults of the Asia and Africa ( like those of Isis, Serapis, Mithras, and Jupiter Sebazios) obviously made their way here, too. The glassware collection is remarkable, as is the jewellery from the "barbarian" tribes of Germany and Southern Russia.
I don't know of many other archeology museums which brings a city back to life so completely like this one. Don't miss it!
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.