The document summarizes key details about the Yenisei River, the fifth longest river in the world located in Siberia. It flows north for 3,487 km through Siberia and is considered the boundary between western and eastern parts of the region. The Yenisei River runs through various climatic zones in Siberia, with camels living upstream and polar bears near its mouth. It is an important waterway for the Krasnoyarsk Territory and a source of oil and hydroelectric power near its mouth.