Combining 2 cities worth of public transport has left Berlin very well covered. The U-Bahn is the underground, while the S-Bahn is the over ground. Buses and trams are also available mainly in the east. Tickets are available from THE WALL machines, service desks with options of DAY, €6.10, WEEK, €22 or a 72hrWELCOMECARD, €19, and work over all transport types.