Simplify the following text for a Grade 6 native English-speaking person.
Original: Mitte encompasses Berlin 's historic core and includes some of the most important tourist sites of Berlin ( like the Museum Island , Brandenburg Gate , Unter den Linden and the Reichstag among others ) , most of which were in former East Berlin .
Simplified: Mitte was in East Berlin , and had a lot of Berlin 's historic sites . The Pergamon Museum , Unter den Linden and the Brandenburg Gate were in Mitte .