- Because of the system described above, you often do not have to enter a bus or tram through the front door. Enter anywhere, stamp your ticket, and you’re good to go.

- Within a given city there are usually myriad metro/bus/tram transfer privileges. Your guidebook should detail these, but an inquiry at the tourist office is advisable as well.

- Most metro systems give out free pocket-sized maps, which can save pulling out your guidebook or unfolding a city map every few minutes.

- Though buses and trams are slower than metros, they offer a much better view, and give you a feel for the cities that contain all those museums, stores, cafes, and monuments you want to visit.