World Cleanup Day is taking place for the 10th time this year. We are going to take this opportunity to do something good for the city. Littering is a huge problem in Berlin too and Mauerpark is no exception. In conjunction with the local organisers wirBerlin, we would like to invite all the friends of Mauerpark, along with local people and visitors, to take action and help make Mauerpark a little bit cleaner....