Pyotr Kozlov in the context of "Petergof"

Nikolay Mikhaylovich Przhevalsky (or Przewalski or Prjevalsky; 12 April [O.S. 31 March] 1839 – 1 November [O.S. 20 October] 1888) was a Russian geographer and a renowned explorer of Central and East Asia. Although he never reached his ultimate goal, the city of Lhasa in Tibet, he still travelled through regions then unknown to Westerners, such as northern Tibet (modern Tibet Autonomous Region), Amdo (now Qinghai) and Dzungaria (now northern Xinjiang). He contributed substantially to European knowledge of Central Asian geography.

Przhevalsky described several species previously unknown to European science, such as Przewalski's horse, Przewalski's gazelle, and the wild Bactrian camel, all of which are now endangered. He was also a mentor of the explorer Pyotr Kozlov.

The Noin-Ula burial site (Mongolian: Ноён уулын булш, Noyon uulyn bulsh, also Noyon Uul) consist of more than 200 large burial mounds, approximately square in plan, some 2 m in height, covering timber burial chambers. They are located by the Selenga River in the hills of northern Mongolia north of Ulaanbaatar in Batsumber sum of Tov Province. They were excavated in 1924–1925 by Pyotr Kozlov, who found them to be the tombs of the aristocracy of the Xiongnu; one is an exceptionally rich burial of a historically known ruler of the Xiongnu, Wuzhuliu, who died in 13 CE. Most of the objects from Noin-Ula are now in the Hermitage Museum in Russia, while some artifacts unearthed later by Mongolian archaeologists are on display in the National Museum of Mongolian History, Ulaanbaatar. Two kurgans contained lacquer cups inscribed with Chinese characters believed to be the names of Chinese craftsmen, and dated September 5 year of Tsian-ping era, i.e. 2nd year BCE.