Ralf was prompt and professional in answering all my questions. Ralf and his driver Mutt were extremely knowedgeable about the city and its history and were able to share that with us very well. Ralf also did well to vary the pace of the day with walking, driving, and touring to take into account the various abilities and interests of the group. Everyone in the group thought both were very friendly. It was a terrific experience from beginning to end - we couldn't have been more pleased.