<P> Germany is known for its many zoological gardens, wildlife parks, aquaria, and bird parks . More than 400 registered zoos and animal parks operate in Germany, which is believed to be the largest number in any single country of the world . The Zoologischer Garten Berlin is the oldest zoo in Germany and presents the most comprehensive collection of species in the world . </P> <P> With an estimated 81.8 million inhabitants in January 2010, Germany is the most populous country in the European Union and ranks as the 15th largest country in the world in terms of population . Its population density stands at 229.4 inhabitants per square kilometre (594 / sq mi). The United Nations Population Fund lists Germany as host to the third - highest number of international migrants worldwide, around 20% of Germany _́ s population do not hold a German passport or are descendants of immigrants . </P> <P> Germany comprises sixteen states that are collectively referred to as Länder . Each state has its own state constitution and is largely autonomous in regard to its internal organisation . Due to differences in size and population the subdivision of these states varies, especially between city states (Stadtstaaten) and states with larger territories (Flächenländer). For regional administrative purposes five states, namely Baden - Württemberg, Bavaria, Hesse, North Rhine - Westphalia and Saxony, consist of a total of 22 Government Districts (Regierungsbezirke). As of 2009 Germany is divided into 403 districts (Kreise) on municipal level, these consist of 301 rural districts and 102 urban districts . </P> <Table> <Tr> <Td> <Table> <Tr> <Th> State </Th> <Th> Capital </Th> <Th> Area (km2) </Th> <Th> Population </Th> </Tr> <Tr> <Td> Baden - Württemberg </Td> <Td> Stuttgart </Td> <Td> 35,752 </Td> <Td> 10,717,000 </Td> </Tr> <Tr> <Td> Bavaria </Td> <Td> Munich </Td> <Td> 70,549 </Td> <Td> 12,444,000 </Td> </Tr> <Tr> <Td> Berlin </Td> <Td> Berlin </Td> <Td> 892 </Td> <Td> 3,400,000 </Td> </Tr> <Tr> <Td> Brandenburg </Td> <Td> Potsdam </Td> <Td> 29,477 </Td> <Td> 2,568,000 </Td> </Tr> <Tr> <Td> Bremen </Td> <Td> Bremen </Td> <Td> 404 </Td> <Td> 663,000 </Td> </Tr> <Tr> <Td> Hamburg </Td> <Td> Hamburg </Td> <Td> 755 </Td> <Td> 1,735,000 </Td> </Tr> <Tr> <Td> Hesse </Td> <Td> Wiesbaden </Td> <Td> 21,115 </Td> <Td> 6,098,000 </Td> </Tr> <Tr> <Td> Mecklenburg - Vorpommern </Td> <Td> Schwerin </Td> <Td> 23,174 </Td> <Td> 1,720,000 </Td> </Tr> <Tr> <Td> Lower Saxony </Td> <Td> Hanover </Td> <Td> 47,618 </Td> <Td> 8,001,000 </Td> </Tr> <Tr> <Td> North Rhine - Westphalia </Td> <Td> Düsseldorf </Td> <Td> 34,043 </Td> <Td> 18,075,000 </Td> </Tr> <Tr> <Td> Rhineland - Palatinate </Td> <Td> Mainz </Td> <Td> 19,847 </Td> <Td> 4,061,000 </Td> </Tr> <Tr> <Td> Saarland </Td> <Td> Saarbrücken </Td> <Td> 2,569 </Td> <Td> 1,056,000 </Td> </Tr> <Tr> <Td> Saxony </Td> <Td> Dresden </Td> <Td> 18,416 </Td> <Td> 4,296,000 </Td> </Tr> <Tr> <Td> Saxony - Anhalt </Td> <Td> Magdeburg </Td> <Td> 20,445 </Td> <Td> 2,494,000 </Td> </Tr> <Tr> <Td> Schleswig - Holstein </Td> <Td> Kiel </Td> <Td> 15,763 </Td> <Td> 2,829,000 </Td> </Tr> <Tr> <Td> Thuringia </Td> <Td> Erfurt </Td> <Td> 16,172 </Td> <Td> 2,355,000 </Td> </Tr> </Table> </Td> </Tr> </Table>

How many states are within germany’s borders