Berlin has two international airports, Berlin Tegel (TXL) and Berlin Schönefeld (SXF) that are connected to Berlin's public transport system. A single ticket from TXL to the city center is currently 2.70 €, from SXF it is 3.20 €.
Directions from the airports to Freie Universität Berlin:
There are a number of train stations in Berlin, the most central being the Hauptbahnhof. Train tickets in Germany can get quite expensive if you do not book in advance. There are some special offers for journeys within Europe and for early bookings. For more information see: www.bahn.de
Departing every 30 minutes, the Deutsche Bahn’s regional express train (RE 1) runs regularly to Frankfurt/Oder calling at the following rail stations in Berlin: Zoologischer Garten, Hauptbahnhof, Friedrichstraße, Alexanderplatz, and Ostbahnhof.