The Moscow Zoo is one of the largest and oldest zoological gardens in Russia. It covers an area of 21.5 hectares and hosts 1,127 different species of animals. Founded in 1864 by a group of biologists from the Moscow State University, it is located near the ring of the gardens, close to the metro stations Barrikadnaja and Krasnopresnenskaja of the Moscow metro. The zoo was founded in 1864 on the initiative of the university professor Anatolij Bogdanov. The construction of the complex was made possible thanks to the funds deriving from the registration fees of a nature promotion association and a donation from the Romanov imperial family. At the opening the zoo occupied an area of about 10 hectares and housed 286 animals. The first structures of the zoo were designed by the Italian architect Pёtr Kampioni. It was mainly wooden buildings with typically Russian stylistic features. At the end of the 19th century, architects Lev Kekusev and Sergei Rodionov were commissioned to design new structures. Between 1905 and 1907 the zoo was involved in the revolutionary events that affected the Russian Empire. The aquarium was destroyed and many of the animals were killed. In 1919, following the Bolshevik revolution, the zoo was nationalized and its management passed to the municipality of Moscow. The park area was enlarged, reaching 18 hectares. The number of animals in it was increased and scientific units, research laboratories and veterinary centers were created. The zoo continued to function regularly even during the Second World War. In 1990 the structure was renovated. In particular, a new entrance and a pedestrian bridge were built to connect the two parts of the zoo, previously divided by the Bol'saja Gruzinskaja road. Furthermore, the dimensions of the structure were further increased. The renovation was dedicated to the eight hundred and fiftieth anniversary of the city of Moscow. Within the zoo, studies are carried out on animal behavior, feeding and reproduction, as well as on rare species in danger of extinction. In 2010, the animals registered in the zoo were 8,556, while in January 2012 there were 7,755.