The Spreewald is situated 100 km south-east of Berlin and designated a biosphere reserve by UNESCO in 1991. It is known for its traditional irrigation system which consists of more than 200 small channels within the 484-square-kilometre area. The landscape was shaped during the ice-age. Alder forests on wetlands and pine forests on sandy dry areas are characteristic for the region, however, also grasslands and fields can be found.As of 1998 about 50,000 people live in the biosphere reserve. Many of them are descendants of the first settlers in the Spreewald region, the Slavic tribes of the Sorbs/Wends. Until today, they have preserved their traditional language, customs and clothing.