Cabriofahrt U Bahn Berlin. The mission impossible bob the builder chose to accept was a connection between the metro lines u5 and u55. This might sound rather easy.
Short for untergrundbahn, underground railway) is a rapid transit system in berlin, the capital and largest city of germany, and a major part of the city's public transport system. This brlin will be operated by driverless trains if the u1 is built. Tariff zones & network maps: