the decades. Weimar is now a popular residence of people working in Erfurt and Jena, both less than 20 minutes away. In 2004, a fire broke out at the Duchess Anna Amalia Library. The library contains a 13,000-volume collection including Goethe's masterpiece Faust, in addition to the duchess's music collection. An authentic Lutheran Bible from 1534 was saved from the fire. The library is one of the oldest in Europe, dating back to 1691, and is listed as a UNESCO World Heritage Site. Over one million volumes were housed in the library, of which forty to fifty thousand were damaged beyond repair. A number of books were shock-frozen in Leipzig to save them from rotting. The library was reopened in 2007. Geography and demographics Topography Weimar is situated within the valley of Ilm river, a tributary of Saale river on the southern border of the Thuringian Basin, a fertile agricultural area between the Harz mountains in the north and the Thuringian Forest in the southwest. The municipal terrain is hilly; the height of the city centre in Ilm valley is approximately 200 m of elevation. To the north, the terrain rises to Ettersberg, the city's backyard mountain, 482 m in height. The range of hills in the south of Weimar rises up to 370 m and is part of the Ilm Saale Plate Muschelkalk formation. The eastern, central and western parts of the municipal territory are in agricultural use, whereas the Ettersberg and some southern areas are wooded. Climate Weimar has a humid continental climate (Dfb) or an oceanic climate (Cfb) according to the Köppen climate classification system. Summers are warm and sometimes humid with average high temperatures of and lows of . Winters are relatively cold with average high temperatures of and lows of . The city's topography creates a microclimate caused through the basin position with sometimes inversion in winter (quite cold nights under ). Annual precipitation is only with moderate rainfall throughout the year. Light snowfall occurs, mainly from December through February, but snow cover does not usually remain for long. Administrative division Weimar abuts the district of Weimarer Land with the municipalities Berlstedt, Ettersburg, Kleinobringen, Großobringen and Wohlsborn in the north, Kromsdorf, Umpferstedt and Mellingen in the east, Vollersroda, Buchfart, Hetschburg, Bad Berka and Troistedt in the south and Nohra, Daasdorf am Berge, Hopfgarten and Ottstedt am Berge in the west. The city itself is divided