This day trip assumes you will arrive in Berlin at the new main train station, this being the first point of interest on the tour. The new station was opened in 2006 and is the largest train junction in Europe. It is massive inside and has many shops and sources of food and drink to choose from. Once you have overcome the challenge of identifying the front entrance from the back, exit the station from the rear and walk out to the traffic crossing next to the river. Cross the Spree River on the footbridge directly in front of you. Follow the sidewalk 500 meters, veering left, to the second point of interest on the tour, the Reichstag building.

The Reichstag building once again became the home of Germany’s Bundestag, or parliament, when it relocated from Bonn in 1999. Transparency and openness are the keys to German democracy and to the Reichstag building itself. From the main entrance of the building, visitors can look directly into the plenary chamber through a glass wall. Once through the sometimes long line outside, take the elevator to the roof and the now-famous glass cupola or dome, which in good weather provides excellent views of the city. There is no entrance fee; only patience is required if the queue is long.

Leave the Reichstag building and head left, towards the Brandenburg Gate (Brandenburger Tor). Walk past the Gate one block, to the third point of interest on the tour, the Holocaust Memorial. In 2005, this memorial to the Jewish victims of the Nazis in World War II was dedicated after much controversy. The memorial is actually a grid of 2711 concrete blocks of varying heights, sitting on undulating ground. Interestingly, there are no markings whatsoever on the blocks. Walk through this seeming maze at will. If you are short on time, skip the Information Center beneath the memorial. There is no entrance fee.

Head back to the Brandenburg Gate and walk underneath it onto Unter Den Linden street. If you turn and face the monument, you will be looking at it from the front. This fourth stop on the tour takes very little time but is significant because it is a symbol of German reunification. It was originally built in 1791 and is the only remaining gate into the city.

Get on the subway about a hundred meters in front of the Gate. A Berlin AB ticket (for zones A and B) will cost 6.10€ and a group ticket for up to 5 people will cost 15.90€. Don't forget to validate your ticket.

Take the S1/S2/S25 line one stop to Friedrichstrasse. Leave by the front entrance and walk along the building supporting the train tracks. It is a 10-minute walk to Museums Island from there.

With only one day in the city, I recommend choosing one museum on the Museums Island: The Pergamon Museum. This fifth stop on the tour boasts the Pergamon Altar, the Market Gate of Miletus, the Ishtar Gate and the Babylonian Processional Way. These are truly impressive to see. You could spend hours at this museum; it is well-worth the entrance fee of 10€.

Upon leaving the museum, turn left and walk a block and a half to the Berlin Cathedral (Berliner Dom), the sixth stop on the tour,. The church, essentially destroyed in one night in WWII, is built in Italian Renaissance style and is topped by a new copper dome. Entrance to the cathedral costs 5€ or 8€ with an audio guide.

Turn left when leaving the cathedral and left again, walking along Karl-Liebknecht-Strasse. An interesting stopping point is the Ampelmann shop, where the East German pedestrian traffic (ampel) signal has become a German icon. Because of the significance of the ampelmann, this is considered stop seven on the tour.

Continue walking along Karl-Liebknecht-Strasse for about 15 minutes. To the right will be Berlin’s famous TV Tower (Berliner Fernsehturm) and the Alexanderplatz. The square was badly damaged during the war and was rebuilt in classic 1960's GDR style. The TV Tower and World Time Clock (Weltzeituhr) are remnants from this period. The cost to ascend the TV Tower is 10€. This is considered the eighth stop on the tour.

End your busy one-day tour of Berlin at the Brauhaus Mitte across the street from the Alexanderplatz train station in the Berlin Carre. They serve traditional Berlin and regional food as well as other German specialties. Beer is brewed on the premises. I recommend the Brauhaus Dunkel.

Head back to the main train station from here. Any of the S5/S7/S75/S9 trains will get you back to the new main train station in only three stops.