If like me later this month, you have a few hours between flights in Berlin, would you rather sit at Tegel Airport and get bored or take a quick look at the city. Only buses serve Tegel.
I asked the very responsive team at Visit Berlin for a couple suggestions on what could be done in 2 to 3 hours, here's their feedback:
1) I could recommend to go to Brandenburg Gate (you can take the bus TXL from Berlin Tegel and step out directly there, takes you 30 minutes). From there you can stroll around the area i.e. the Boulevard Unter den Linden with the famous Hotel Adlon or go to the nearby Reichstag where the German Parliament has its seat. From there you can walk to Hauptbahnhof and take the bus TXL back to Tegel Airport. From the Brandenburg Gate you could also walk to Potsdamer Platz and you will pass the Memorial to the Murdered Jews of Europe.
2) You could also go to the famous boulevard Kurfürstendamm (take Bus 109 to ‘Kurfürstendamm’, takes you not more than 30 minutes) and take a look on Gedächtniskirche and stroll around the shopping street to have a first impression of Berlin.
Ticket from Berlin Tegel Airport to Berlin City Centre costs only 2,30 € each way or 6,30 € for a 1 day ticket for unlimited travel.
If I need a sugar kick I might make a quick stop at Ritter Sport Chocoworld, Französische Strasse 24.
(* Image of Ritter Sport Chocoworld from Visit Berlin site)