My family and I recently visited Berlin for a few days. We booked a full day with Klaus Kannen. It was the highlight of our trip. We started at 9am and went until 6pm. Klaus was not only early but was very warm and welcoming. We made at least 12 stops and one for lunch. We asked hundreds of questions. He delightfully answered each on of them with a smile and great knowledge. I will come back and will book him again. He is a 10 on a 1-10 scale. I can't reccomend him enough. I asked him where I could leave this review because this guy should be booked every single day.