Along Karl-Marx-Alle, formerly known as Stalin-Allee, stand a series of socialist apartment blocks built in the early 1950s by the East Germany government as an after-war reconstruction effort. Modernist straight lines decorated with classical details, the style known as Stalinist architecture, appear luxurious to me. Get off at Strausberger Platz U-bahn station (on Line U5) and walk to the east, to enjoy the idealism of early-day communist Germany.
On Bernauer Strasse in the north of Berlin remains a stretch of the Berlin Wall. 
This is where the Wall brutally cut the community into half, by running just in front of the local church so residents on the western side of the Wall could not walk into it. 
Residential buildings in the eastern side of the Wall were demolished so that East Germany's officials on a watchtower could keep watch on the wall to shoot anyone who tried to escape from the communist part of the city.
The East Germany government destroyed the defunct church in 1985. 
When the Wall was brought down, people here decided to erect a modest-looking chapel in the same place as where the church used to stand. 
Initially I didn't know what this oval-shaped building is meant for. After I learned about the history of the church, I noticed the cross in front of the chapel, which almost made me cry.
The stretch of the land along Bernauer Strasse where the demolished residential buildings on the Eastern side of the Wall used to stand is mostly empty, suggesting the land title for the area hasn't been solved yet. You need to come down here to feel what the Berlin Wall was like. (The official website of the Berlin Wall Memorial on Bernauer Strasse is here.)
A billboard standing at the site of the Berlin Wall Memorial
Berlin's answer to the Effel Tower in Paris is Fernsehturm (TV Tower). When I saw it in a photo before arriving in Berlin, I didn't really understand why it has become Berlin's icon.
Once I'm walking around the city, I understand why. Its view is simply ubiquitous. Almost anywhere in Berlin you will notice its presence.
Even Berlin's other landmarks such as Brandenburger Tor and Berliner Dom are haunted by the TV Tower.
The more I see the tower's futuristic design, the more I feel affinity to it.
Although it was erected by the atheist communist government in 1969, the cross appears on the ball when it's sunny (known as Pope's Revenge).
West Berlin failed to produce such a landmark. Although the West won the Cold War, the East scored in this respect.
Ranked 8th in this year's world nightclub ranking by DJmag, Watergate is actually more like a great bar than a nightclub though the gate is open at midnight, the DJ listing is serious, and the best DJ starts playing after 4:30 am. Facing on the river Spree, both of its two dancefloors feature floor-to-ceiling glass windows through which you enjoy the view of Oberbaum Bridge, the neon sign of Universal Music Group, the river water surface glittering. What's more, there is an open-air terrace on the river that can be accessed from the club where you can chill out after an intense dance session with minimal techno rhythm. The only problem is people smoke inside, making your clothes stink, something that I thought was a thing of the past after even UK bans smoking inside the buildings.
Jewish Museum Berlin has another corridor called the Axis of Exile. A brief description that German Jews had to emigrate outside Europe (from the Americas to Shanghai) as European countries were reluctant to accept them is followed by a square garden outside the museum building where a grid of tall rectangular concrete pillars stand upright against the ground. On top of these pillars thrive olive leaves which are beyond your reach. The pebbled ground is difficult to walk on, but you'll soon realize that it is difficult to keep your balance as you walk around (although what you see is all orderly). 
It turns out that the ground surface of the garden is actually a slope. The right angle formed by the pillars and the ground deceives you into a wrong sense of gravity. And it is not that difficult for someone like me who needs to live abroad (though the reason for it is much, much less tragic in my case) to understand what this garden all means.
A view of the Garden of Exile from above.
On a corridor called the Axis of Holocaust in Jewish Museum Berlin, visitors encounter a series of items left by those Jew victims of Holocaust. There is a door at the end of the corridor. Open it to enter the next room, and you'll be surrounded by darkness with a slit of sunlight high above. You barely hear the sound outside. Concrete walls shape the long triangle space. Sit down on the cold floor and look up at the bright slit, and you'll feel the same as those Jews without the means of fleeing Nazi Germany who hid themselves only to wait for Nazi to take them away to extermination camps.
The second alternative area of Berlin is the Scheunenviertel, the northern half of Mitte district. Auguststrasse, the street where the whole contemporary art scene in Berlin initiated, is full of galleries though few are really impressive. Time Out, who says "many of the cutting-edge galleries have moved on", seems correct. Still, wandering on this street is fun.
Berlin has at least four different areas of boho, alternative, street youth culture. Prenzlauer Berg, northeastern Berlin, is one of such areas. The Time Out Berlin guidebook says that those really cutting-edge already left this area, but Kastanienalle, a street running to the southwest from Eberswalder Strasse U-bahn station, is full of independent boutiques, cafes, and graffiti on houses built at the turn of the 20th century.
When my friend and I were walking along the Spree river, the Berlin Cathedral suddenly appeared on our left, interrupting our conversation with its solemn appearance.
Berlin's Holocaust Memorial turns out to be a maze. Once you walk into the grid of concrete blocks, you are lost because these slabs are much higher than your height in the central area of the memorial premise.
It seems none of the top surfaces and the side walls of these slabs is exactly in parallel. Each concrete slab has no frill on it. They are simply immaculate concrete blocks. Such simplicity and abstractness paradoxically tells visitors the graveness of what this memorial commemorates.
