Prioksko-Terrasny Nature Biosphere Reserve, located near the city of Serpukhov, is Moscow Oblast’s only nature reserve. Despite the fact that it is one of the smallest reserves in Russia, the role it plays in the preservation and research of nature cannot be underestimated with the flora and fauna in the park catching the eye of scientists long ago. In 1861 Moscow State University professor Nikolai Kaufman found steppe grass on the left bank of the Oka River — something completely uncharacteristic for the Moscow area and it is still a mystery as to how such plants found their way to the steppes. It is well-known that the reserve’s bison farm is one of only a few places on earth where zoologists are working to restore the population of the largest cloven-hoofed animals in Europe. In hopes of preserving the natural environment, Dubrovnik is the only territory on the reserve where tourists are allowed. The rest of the park is open only to employees and scientists to ensure that no outside influences alter the natural development of the ecosystem.