Ulaanbaatar, formerly anglicised as Ulan Bator (Улаанбаатар,, literally "Red Hero"), is the capital and largest city of Mongolia. The city is not part of any aimag (province), and its population was over 1.3 million, almost half of the country's total population. Located in north central Mongolia, the municipality lies at an elevation of about 1300 m in a valley on the Tuul River. It is the country's cultural, industrial and financial heart, the centre of Mongolia's road network and connected by rail to both the Trans-Siberian Railway in Russia and the Chinese railway system.
The city was founded in 1639 as a nomadic Buddhist monastic centre. It settled permanently at its present location, the junction of the Tuul and Selbe rivers, in 1778. Prior to that occasion it changed location twenty-eight times, each new location being chosen ceremonially. In the twentieth century, Ulaanbaatar grew into a major manufacturing center. Ulaanbaatar is a member of the Asian Network of Major Cities 21. The city's official website lists Moscow, Hohhot, Seoul, Sapporo and Denver as sister cities.
Ulaanbaatar has been given numerous names in its history. Before 1911, the official name was Ikh Khüree (Их Хүрээ, "Great Settlement") or Daa Khüree (Даа Хүрээ, dà, "great"), or simply Khüree. The Chinese equivalent, Dà kùlún (大庫倫), was rendered into Western languages as "Kulun" or "Kuren".
Upon independence in 1911, with both the secular government and the Bogd Khan's palace present, the city's name changed to Niĭslel Khüree (Нийслэл Хүрээ, "Capital Camp"). It is called Bogdiin Khuree (Богдын Хүрээ, Bogdiĭn Khüree, "Great Holy Khan's Monastery") in the folk song "Praise of Bogdiin Khuree". In western languages, the city at that time was most often referred to as Urga (from Өргөө, Örgöö, "Palace").
When the city became the capital of the new Mongolian People's Republic in 1924, its name was changed to Ulaanbaatar (Улаанбаатар, Ulaanbaatar, classical Mongolian Ulaganbagatur, literally "Red Hero"). On the session of the 1st Great People's Khuraldaan of Mongolia in 1924, a majority of delegates expressed their wish to change the capital city's name to Baatar Khot ("Hero City"). However, under pressure from Turar Ryskulov, a Soviet activist of the Communist International, the city was named Ulaanbaatar Khot ("City of Red Hero").
In Europe and North America, Ulaanbaatar continued to be generally known as Urga or Khure until 1924, and afterward as Ulan Bator (a spelling derived from Улан-Батор, Ulan-Bator). The Russian spelling ("Улан-Батор") is the Russian phonetic equivalent of the Mongolian name, according to Russian spelling conventions. This form was defined two decades before the Mongolian name got its current Cyrillic script spelling and 'Ulaanbaatar' transliteration (1941–1950); however, the name of the city was spelled Ulaanbaatar koto during the decade in which Mongolia used the Latin alphabet. Today, English speakers sometimes refer to the city as UB.