Just for your interest, these are the many ways that you can choose to take a sightseeing tour around Berlin:

Walking, bus, horse drawn carriage, balloon, Douglas DC 3 plane, Travi car!

Also bikes of many varieties - 2 wheeled, fat tires, scooter, 3 wheeled bike, tandem bike, 5 person bike, taxi bike.

Also, limousine if you really must!

This is a tourist mecca, and it is not surpising as this city may not be particularly beautiful, but is an open history book with many stories from throughout history to tell!

Many monuments, particularly related to WW2 are spread throughout the city - there has clearly been a lot of thought put into rebuilding a new city following the war, but without forgetting the past!