Checkpoint Charlie once marked the most controlled doorway between two worlds. It was the only crossing that allowed foreigners to move between East and West Berlin, while local residents on either side could not use it. This strict rule helped build its reputation as a place of secret meetings, coded messages, and quiet exchanges during the Cold War. Its name came from the NATO phonetic alphabet, following Checkpoints Alpha and Bravo at the autobahn crossings of Helmstedt and Dreilinden.
The atmosphere around Checkpoint Charlie turned electric on 27 October 1961. On that day, American and Soviet tanks faced each other only about 200 meters apart. The standoff lasted hours and brought the city to the edge of crisis, underlining just how fragile the peace felt at this border point.
Much has changed since the Wall came down. Sections of the Berlin Wall were removed to make way for new buildings, including the American Business Center and other developments. The junction of Zimmerstraße and Friedrichstraße, near U-Bahn Kochstraße (U6), still displays the famous sign that reads, “You Are Leaving the American Sector.”
The original guardhouse from Checkpoint Charlie is no longer on the street. It moved to the Allied Museum on Clayallee, where it is preserved as a historical object. Nearby, the Haus am Checkpoint Charlie offers a more colorful experience. This private museum exhibits memorabilia connected to the Wall and showcases the inventive devices used by people fleeing the GDR—among them, a tiny submarine that once carried escapees beneath the water.
Street vendors in the area sometimes offer “passport control” booths where they stamp souvenir marks for a small fee. These stamps are not official and could invalidate a current passport. A safer option is to bring an expired passport or a small notebook to collect the stamps without risking travel documents.
Source - https://en.wikipedia.org/wiki/Checkpoint_Charlie
The zoo in the former East Berlin is more spacious than its West Berlin counterpart, the historic Berlin Zoo and has been open for some 50 years. The Tierpark has nearly as many animals, but fewer reptiles and aquatic animals. It appears rather like a park with animals than a classic zoo, in fact it is one of the biggest zoos in Europe. There is an old castle from the late 17th century in the northeast of the Tierpark (Schloss Friedrichsfelde).
The district town hall was the main town hall for West Berlin during the Cold War. The freedom bell (a present from the American people) and several memorials from that time can be found here. On the main balcony in 1963 U.S. President John F. Kennedy made his famous statement, "All free men, wherever they may live, are citizens of Berlin, and, therefore, as a free man, I take pride in the words ‘Ich bin ein Berliner!’". On 10 November 1989 Helmut Kohl (chancellor (Bundeskanzler) 1982-1998) and Willy Brandt (former Bundeskanzler and mayor of Berlin) cheering the crowd as they saw the end of the Berlin Wall the night before. The town hall is an emotional place for most people in Berlin (especially West Berlin).
The largest aquarium in Germany with over 9000 animals that are presented on three storeys in a historic building. Aquarium Berlin is found on the premises of the Zoo, but can also be visited separately. One of the best places on a rainy day with children.
Berlin's biggest lake and popular resort for bathing and watersports. You can also travel there by tram, which is an experience by itself.
Exhibition of digital interactive entertainment culture. You can actually play almost all of the exhibits making it a more "hands on" museum than most.
Huge technical museum, on a former railroad depot, featuring from ancient water and wind mills to computer pioneer Konrad Zuse's inventions, a collection of old to new vehicles of all types -bicycles, boats, trains, etc - and the interactive Spectrum science center with various hands-on experiments. There's an actual C-17 "Candy Bomber" airplane hanging on its façade. The railroad and aeronautical sections are hard to beat.
Jewish cemetery and lapidarium with old tombstones.
It is the only hemp museum in Germany; you can see the history of hemp, the culture and use of it. You can see hemp grow. There is a cafe downstairs, with an open WiFi access. Everything going on here is legal - including the hemp growing under artificial light (a low THC strain grown with a special permit) - but they do not refrain from political commentary on the legal situation of cannabis in their exhibits.
House museum on Max Liebermann, German painter and printmaker. Has about 15 Lieberman paintings.
A domed church at Bebelplatz/Unter den Linden, the oldest (mid-18th century) and one of the biggest Catholic churches in Berlin. Interior was redesigned in a modern style in the 1950s, but there are still many treasure chambers in the basement.
Again one of the world's most comprehensive ones. At the museum district of Dahlem.
Want to feel like one of the angels in Wim Wenders' classic film Der Himmel über Berlin (a.k.a. Wings of Desire)? Climb to the top of Gold-Else, as the statue of Victory on the top of the Victory Column is known. Just don't jump off if you're not actually an angel. Unfortunately there is no elevator, so be prepared for 285 steps to the platform at 50.7 m.Else was built to commemorate Prussian military prowess in the wars against Denmark (1864), Austria (1866) and France (1870-71), and moved to her present location by the Nazis. Five roads run into a traffic circle called Grosser Stern, in the centre of which is the Siegessäule. Else is visible from much of the city district known as Tiergarten. At the base of the statue are reliefs of war scenes representing the conflicts which this monument memorializes. The Allies forced Germany to take those panels down in 1945, but they were remounted in 1984 and 1987. It also served as a backdrop for a speech by then senator Obama in 2008, after his request to speak in front of Brandenburger Tor caused a political debate in Germany.