A mother carries her child bicycle through the streets of Prenzlauer Berg. Prenzlauer Berg is a locality of Berlin, forming the southern part of the borough of Pankow. Until 2001, Prenzlauer Berg was itself a borough of Berlin; in that year it was merged (together with the former borough Weißensee) into the borough of Pankow. After German reunification in 1990 Prenzlauer Berg became a centre for more bohemian Berlin youth, while more recently it has experienced gentrification. Prenzlauer Berg is a portion of the Pankow district in northeast Berlin. On the west and southwest it borders Mitte, on the south Friedrichshain-Kreuzberg, on the east Lichtenberg, and on the north Weißensee and Pankow. Geologically, the district lies entirely on the Barnim glacial deposit and borders from the southwest (to Mitte) on the Berlin glacier valley, which was formed in the Ice Age. The highest point of the district is 91 meters above sea level in the northwest of Volkspark Prenzlauer Berg. This hill came into being after World War II, created from one of the debris piles after the gathering of rubble from the city center and the subsequent rebuilding.