Tegel Airport (Berlin)   
Berlin Tegel Airport (IATA: TXL) is the main international airport of Berlin, the federal capital of Germany, ahead of the smaller Berlin Schönefeld Airport. It is christened after Otto Lilienthal and is the fourth busiest airport in Germany with just over 19.59 million passengers in 2013.[1] The airport is a hub for Air Berlin and serves as a base for Germanwings. It features flights to several European metropolitan and leisure destinations as well as some intercontinental routes.

It is situated in Tegel, a section of the northern borough of Reinickendorf, 8 km (5.0 mi) northwest of the city centre of Berlin. Tegel Airport is notable for its hexagonal main terminal building around an open square, which makes for walking distances as short as 30 m (98 ft) from the aircraft to the terminal exit. The airport is scheduled to be closed when the new Berlin Brandenburg Airport opens, not before 2017. Wikipedia
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TXL JetExpressBus
TXL -> Alexanderplatz


40 mins (depend on the traffic)

TXL -> Alexanderplatz


20-27 mins (depend on the traffic)

X9 JetExpressBus
TXL -> Zoologischer Garten


20 mins (depend on the traffic)