Ulaanbaatar was founded in 1639. Zanabazar, son of Tusheet Khaan Gombodorj, the most powerful and influental among Khalka's Khaans was proclaimed as the religious leader of Mongolia due to the strong influence of Buddhism in the country. And a special monastery complex was built for him as headquarters. The headquarters became the foundation of the former Urgoo (means palace), present Ulaanbaatar. The city hosts the only international airport of the country and single international rail line. The Trans Siberian railway goes across the city from the north to the south. Ulaanbaatar, with approximately a million of population, is the country's economic, cultural and political center and has a number of tourist's attractions and hosts most varied types of entertainment. Ulaanbaatar is located on the bank of Tuul river and sorrounded by four sacred mountains with dense pine forest on the northern slopes and grassy steppes on the south. Mostly described, as sunny, peaceful and open, Ulaanbaatar is city of contrast where modern life comfortably blends with Mongolian traditional lifestyle.