If you google "Berlin" , you will probably see Brandenburg Gate :) So don't forget to visit it. It worths to visit. It is especially a great place when you visit with a local guddy. See the link. Read more.
Checkpoint Charlie is the crossing point between East Berlin and West Berlin during the Cold War (1947 - 1991) It is a must see place if you are interested in history of Berlin. Read more.
Berlin Wall was built in 1961 and remained as a barrier untill 1989. It was dividing Berlin into two sides as West Berlin and East Berlin. Now it is covered with beautiful Graffitis Read more.
Teufelsberg is a hill made of rubble that covers an under-construction Nazi military-technical college. There was a spy station on the hill, that was used by the NSA during the Cold War. Read more.
After a long day of walking through Berlin streets, banks of Landwehr Canal is the best place to take a rest. You can also sit on gras, smoke or drink there with other people. Read more.
On Sunday, you should visit Mauerpark. There are public Karoke performances in the park. Overcome your fears and get on the stage to sing a song. I am sure you will remember those moments. Read more.
Berlin has many abandoned buildings & many people come to Berlin just to see these abandoned buildings. Konigin Elisabeth Hospital is one of them. Opened in 1843. Click to see an abandoned place tour: Read more.
Rent a bike and go to Tiergarten which is Berlin's the greenest park. Be careful, It is so huge and you can get lost there :) But definitely it is one of the best places to take a rest. Read more.