Not only is Berlin the largest city in Germany, it is also the capital. Given the historical significance of this European city, it is no wonder Berlin ranks high on any travelers list of cities to visit.
Berlin has some unique tours for you to partake in. Brewer's Berlin Walking Tour is exactly what it sounds like. This free tour introduces you to the city's history while you spend the day walking and sampling the finest beers available. There are several Jewish tours which focus on the history of Berlin Jews and several will visit the nearby Sachsenhausen Concentration Camps. Bike tours are a popular way to see Berlin. The city is relatively flat and there are numerous bike paths throughout the city.
How to spend your evening can be a difficult decision given all the choices. There are four major opera houses in Berlin. Staatsoper Unter den Linden is a masterpiece of architecture and a truly historic venue to experience Wagner in. If you prefer the theater, you will have no shortage of options. Take in a cabaret one night and a contemporary play the next. For a more active evening, the Berlin club scene is sure to delight. It is easy to have a new adventure every night since Berlin has more than 200 clubs. Mitte, Friedrichshain-Kreuzberg and Prenzlauer Berg are the main clubbing districts. While the clubs are open every night of the week, Thursday through Saturday are the busiest nights. Most close around 3 AM but there is a strong after hours scene dominated by techno.
Berlin is a multi-cultural city and this is clearly reflected in the plethora of dining choices. No matter what cuisine you may be craving, you will be faced with many options. One thing you must try is the currywurst. This is Berlin staple consisting of a bratwurst smothered in curry powder and ketchup. Finding one will not be difficult since almost every street vendor stocks it.
If you travel in a group you could make a trip to the country side and explore one of the great high ropes course in Berlin (here you get further information (german)).
When you finally visit Berlin, be sure and set aside more than a weekend for the experience. Better yet, make Berlin an annual pilgrimage.