Ferry transport forms part of the transport network of Berlindue to the city's extensive network of rivers, lakes, and canals. 6 routes operate within the city boundaries and one serves the city of Potsdam, which are part of the common public transport tariff run by the Verkehrsverbund Berlin-Brandenburg (VBB). Outside of this system there a private and tourist ferries, the Straussee Ferry is notable as it is one of only a handful of electrically operated cable ferries in the world.