in November 1930. The national airline Aeroput included Niš as a regular destination for the route Belgrade—Niš—Skopje—Thessaloniki in 1930. During the time of German occupation in World War II, the first Nazi Crveni Krst concentration camp in Yugoslavia was in Niš. About 30,000 people passed through this camp, of whom over 10,000 were shot on nearby Bubanj hill. On February 12, 1942, 147 prisoners staged a mass escape. In 1944, the city was heavily bombed by the Allies. On October 14, 1944, after a long and exhausting battle, the 7th German SS Division 'Prinz Eugen' was defeated and Niš was liberated by Bulgarian Army, and Partisans. The city was also the site of a unique and accidental friendly fire air war on November 7, 1944 between the air forces of the United States and Soviet Union. On June 23, 1948, Niš was the site of a catastrophic flood during which the Nišava river's water level raised by an unprecedented 5.5 meters. After World War II, the University of Niš was founded on June 15, 1965. Over the course of the 1999 NATO bombing of Yugoslavia, Niš was subject to airstrikes on 40 occasions. On May 7, 1999, the city was the site of a NATO cluster bomb raid which killed up to 16 civilians. By the end of the NATO bombing campaign, a total of 56 people in Niš had been killed from airstrikes. 2000–present In April 2012, the Russian-Serbian Humanitarian Center was established in the city of Niš. In December 2017, a new building of Clinical Centre of Niš spreading over 45,000 square meters was opened. Geography The road running from the North, from Western and Central Europe and Belgrade down to the Morava River valley, forks into two major lines at Niš: the southern line, leading to Thessalonica and Athens, and the eastern one leading towards Sofia and Istanbul. Niš is situated at the 43°19' latitude north and 21°54' longitude east, in the Nišava valley, near the spot where it joins the South Morava. The main city square, the city's central part, is at above sea level. The highest point in the city area is "Sokolov kamen" (Falcon's rock) on the Suva Planina (Dry Mountain) () while the lowest spot is at Trupale, near the mouth of the Nišava (). The city covers of five municipalities. Below Niska Banja and Nis, under the ground is a natural source