Day one in Berlin was a catch up day for me. I found a laundromat near my Airbnb and did laundry. I struggled a bit with the language barrier, but friendly locals were more than happy to help out. After that I found a small grocery store, loaded up on snacks and spent the evening relaxing in the Airbnb for the first time in about two weeks.
My first full day in Berlin was spent hitting museums and exploring. I did the DDR museum, spent some time at the Holocaust Memorial, and found Checkpoint Charlie. The DDR museum was a fantastic look into Germany's history. I would recommend going during slow hours because it was super busy and getting to check out all the exhibits was difficult at times. The Holocaust Memorial is an absolutely stunning piece of artwork and is a nice place to reflect. Checkpoint Charlie was slightly disappointing because it felt very touristy, and not as great of a representation of Cold War Germany as I hoped.
I continued my walk along the old canal that was the border between East and West Berlin and found the East Side Gallery. This old part of the Berlin wall has been turned into an art instilation and is really cool to get to walk through.
That night happened to be the last night of the Festival of Lights in Berlin. Wandering through the city, seeing all the iconic buildings being lit up was absolutely amazing, and if you can time your trip to Berlin during this, it's a must see experience.
I also went through the Germany History Museum that covered the entire history of the country. I spent hours wandering through, seeing everything from early Germany all the way up to post WWII Germany. It was a neat insight into their rich history. A must do if you're looking to hit a museum on Museum Island.
The German Film Museum, while a little out of the way is also a must do for any film history fan.
My next day was spent at Sachsenhausen Concentration Camp north of the city. We took the train from the Brandenburg Gate up to the same train station the prisoners were taken to, and took the fifteen minute walk from there to the camp. Our tour guide was full of knowledge and was super engaging and passionate about Nazi Germany's history.
We spent the rest of the day getting a crash course in the history of the camp, and the Holocaust and while the day was exhausting emotionally, was worth it 100%.