Here is an alphabetical listing of cities which have a metro (also called underground or subway) system. In this listing, the local names (if any apply) of the transport system are mentioned as well. Some systems that are called light rail, but are essentially a metro system, are also included.
Berlin, Germany (two systems that fit the underground definition, one called "S-Bahn", the other "U-Bahn". They are still separately administered for historical reasons. The U-Bahn is operated by the "BVG[?]" (Berliner Verkehrsbetriebe; Berlin Traffic Works), which is owned by the city of Berlin (and which operates Berlin's tramways and buses as well), while the S-Bahn is operated by the "S-Bahn Berlin GmbH", a subsidiary of the "Deutsche Bahn" (German Railways))