Germany
Unless you want to use the discounts and free-entry options its cheaper to buy one-day transport cards than the three-day Berlin welcome card. Note that both Schonefeld and Tegel airports are within the area for the card, so get it on arrival at the airport.
Find the local transport desk at Tegel (not obvious - ask) or get cards at the train station ticket office (above ground - don't head down the subway) at Schonefeld
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