Thanks, Erbse. No there wasn't any specific reason to visit any of those cities. Just a choice of cheap flight from London and high concentration of attractions in a relatively compact area easily navigable by car which allowed me to see more in 5 days than I could see anywhere else.Some awesome looking stuff Pansori! I'm looking forward to further impressions of your trip
Which place did you like best? And is there a special reason for you to visit Frankfurt, Wiesbaden, Köln, Düsseldorf, Koblenz and Trier?