Phnom Penh wasn't established as the capital of Cambodia until the 15th century when King Ponhea Yat abandoned Angkor and established the capital and five wats at Phnom Penh. The new location had a more central location and wasn't as vulnerable as Angkor to attacks from the Kingdom of Siam. The position was also important for its proximity to two rivers, the Mekong, for trade with Laos and China, and The Tonle Sap, for access to the rich fishing lakes. Although this trade helped Phnom Penh to grow into a regional power, the city didn't enjoy a stable future. Cambodia became somewhat trapped between Thailand and Vietnam and the city was all but destroyed in the late 18th century. This followed a period of rapid development, and by the 1920s, Phnom Penh was nicknamed the 'Pearl of Asia' and considered the most beautiful city in the region. During the first half of the 20th century this development continued with the construction of Pochentong International Airport and the railway to Sihanoukville, which greatly improved the city's transport links. Progress was checked in the 1960s and 70s during the Vietnam war as Cambodia was used as a military base by the Viet Cong and North Vietnamese Army. Phnom Penh saw a great influx of refugees escaping fighting between government troops, the south Vietnamese and the Khmer Rouge. In 1975, Phnom Penh was under siege and fell to the Khmer Rouge on April 17th. The Vietnamese liberated Phnom Penh in 1979 and slowly people began to return to the city. There followed a period of reconstruction funded by aid and foreign investment and loans from the Asia Development Bank and World Bank helped to re-establish a solid infrastructure in the city. At the turn of the millennium, the population was back to over one million and attracting an increasing number of visitors. | 
