Try to guess 20 first level administrative subdivision capitals (both in Germany and other countries) closest to Berlin.
For practical reasons, I'm making some exceptions in this series. Relevant exceptions for this quiz are:
For Luxembourg, Liechtenstein, San Marino and Andorra, only country capital and largest (second largest if capital's the largest) municipality seat are included.
Capitals of Belgian provinces are included.
National capitals that aren't subdivision capitals are included.
If some subdivision capitals are omitted but should be included, please let me know.