Considering the Berlin-Paradies in Berlin?
A VT member wrote the following comment about visiting Berlin:
Getting around in Berlin by Canuck5
Berlin has a great transit system. If you're arriving in Berlin without a car, don't bother renting one. Between the streetcars, the subway, the train, and the buses, you'll have no trouble making your way around the city.
Plain-clothed Inspectors do spot-checks to ensure passengers have tickets, but it's mostly an honor-system. I never got checked once, but a friend of mine got checked twice in one day.