the Moscow Zoo is the largest and oldest zoo in Russia. It was founded in 1864 by a group of professor-biologists, K.F. Rulje, S.A. Usov and A.P. Bogdanov, from the Moscow State University. In 1919, the zoo was nationalized. In 1922, the ownership was transferred to the city of Moscow and has remained under Moscow's control ever since. The zoo had an area of 10 hectares when it first opened, with 286 animals. In 1926, the zoo was expanded to adjacent lands, increasing the area to 18 hectares. The zoo's original buildings were wooden, built in the old Russian style with intricate wood trims. In 1990, the zoo was renovated. Notable additions include a footbridge that connected the old (1864) and new (1926) properties of the zoo (prior to this, the zoo operated as two 'separate zoos' as the Bolshaya Gruzinskaya Street divided the two properties) and a new main entrance in the shape of a large rock castle. Waterfalls and streams were added throughout the zoo to give the zoo a more natural feeling. In addition, the zoo was expanded once more.