The Tuul River coming from the Khentii Mountains is 819 km long and joins the Orkhon River. A lot of big and small rivers join with the Tuul River. Although the river is mostly rocky in the upstream, it is surrounded by a willow forest when it gets through Ulaanbaatar city. In the 1950s when fire wood was used to create a raft the water level of the river was much higher. The river Tuul is one of three famous Mongolian rivers. It will be forever kept sacred in the history of Mongolia. It is also mentioned frequently in the book of Mongolian secret history. Since ancient time, the river has been affectionately referred to as "queen Tuul" because Mongolians believe that the river Tuul is the most gracious and forgiving to women.