includes the Sochi National Park (IUCN management category II). It hosted the rare Caucasian wisent, but the last three animals were killed in 1927. In 1940, a group of wisent-American bison hybrids were released into the Caucasian Biosphere Reserve. These hybrids are described as a different subspecies, the highland bison (Bison bonasus montanus). The first medical research institution was established in Sochi in 1936 and named after Stalin. Between 1936 and 1939 it was led by professor (and then academician) A. I. Nesterov and included laboratories and 4 hospitals with the total of 200 beds. The research of that institute was focused on balneotherapy and physiotherapy. In January 1934, Sochi was included in the list of the first-priority expansion areas of Soviet Union (which was usually reserved for industry). As a result, by 1940 the city contained more than 60 sanatoriums and hospitals with the total capacity of about 9,000 beds. In comparison, in the late 1920s, there were only 6 sanatoriums with 465 beds. The development of Sochi was promoted by Joseph Stalin who had his favorite dacha built in the city – a tradition followed by most succeeding Soviet and Russian leaders. Those dachas were used not only for personal leisure, but also hosted numerous (less formal) meetings with high-ranking foreign officials. World War II and after During World War II, the entire city became a hospital for the wounded at the Eastern Front; about 500,000 soldiers convalesced in the 111 hospitals of Sochi during that period. About 2,000 donors contributed 20 tonnes of blood for this purpose; also, 18,707 citizens were mobilized into the Army; of them 4,566 were killed and 17 were awarded the Hero of the Soviet Union award (8 posthumously). Katyusha rocket launchers were mass-produced in the city around 1942–1943 when the frontline was at times 25 km north from Krasnaya Polyana. For its achievements during the war, the city was awarded the Order of the Patriotic War in 1980. Its resort infrastructure was partly destroyed during the war and rebuilt by the early 1950s. After the war, the city kept its position as the leading sanatorium and health resort of the Soviet Union. By the 1960s, it was receiving about 500,000 visitors per year, i.e. about four times its population. This motivated the government to expand the city by including the Adler and Lazarevskoye districts. By the 1980s, the number of tourists rose