Given the task definition and input, reply with output. In this task, you are given Wikipedia articles on a range of topics, we ask you to write a question based on the content of the articles that can be answered in a binary manner i.e. True or False.

West Berlin -- On 9 November 1989, the Wall was opened, and the two parts of the city were once again physically--though at this point not legally--united. The Two Plus Four Treaty, signed by the two German states and the four wartime allies, paved the way for German reunification and an end to the Western Allies' occupation of West Berlin. On 3 October 1990--the day Germany was officially reunified--East and West Berlin formally reunited as the city of Berlin, which then joined the enlarged Federal Republic as a city-state along the lines of the existing West German city-states of Bremen and Hamburg. Walter Momper, the mayor of West Berlin, became the first mayor of the reunified city.
is there still an east and west berlin