Berlin is an amazing city! I fell in love with it during my four day visit. I remember the cold war and I remember when the wall came down, but I really didn’t have a grasp of the history of the wall or the significance of it coming down for the people of Berlin and Germany. I learned so much when I was there. I highly recommend Insider Tours for a walking tour of the city. They offer a great overview of the city and its rich history. Best 12 euros you will spend while there!
Also, the alternative Berlin walking tour is great too! You will see the underside of Berlin, the street art, the east gallery, the coffee houses and funky shop and stories. It’s technically free; the guides work for tips. Awesome experience!