The City of London is one of the most important financial districts in Europe. In this area of London many people are concentrated during the day as they go to work, but at night it is very quiet as the weekend.
I went to Berlin some years ago, it was during the summer, the weather was quite hot for being Berlin. There was a lot of people in the streets and a lot of activities to do. To visit the Brandenburg Gate, the Reichstag, and the River Spree and the amazing park Tiergarten.