Brandenburg (Lower Sorbian: Bramborska; Upper Sorbian: Braniborska) is one of the sixteen federal-states of Germany. It lies in the east of the country and is one of the new federal states that were re-created in 1990 upon the reunification of the former West Germany and East Germany. The capital is Potsdam. Brandenburg surrounds but does not include the national capital and city-state of Berlin. Originating in the medieval Northern March, the Margraviate of Brandenburg grew to become the core of the kingdom, later Free State of Prussia. The eastern third of historic Brandenburg (Ostbrandenburg/Neumark) was ceded to Poland in 1945. Brandenburg is known for its well-preserved natural environment and its ambitious natural protection policies which began in the 1990s. 15 large protected areas were designated following Germany’s reunification. Each of them is provided with state-financed administration and a park ranger staff, who guide visitors and work to ensure nature conservation. Most protected areas have visitor centers.