Phnom Penh [a] is the capital and most populous city of Cambodia. It has been the national capital since 1865 and has grown to become the nation's primate city and its political, economic, industrial, and cultural centre. The city's name derives from Wat Phnom, a Buddhist temple, and Lady Penh, the city's founder. It sits at the confluence of the Tonlé Sap and Mekong rivers, and is the start of the Bassac River. It is also the seat of Cambodia's monarchy, based at the Royal Palace. Founded in 1372, Phnom Penh succeeded Angkor Thom as the national capital in 1434 following the fall of Angkor, and remained so until 1497.[9] It regained its capital status during the French colonial era. It underwent a period of investment and modernization during Cambodia's independence period, earning the nickname the "Pearl of Asia" for its colonial French, New Khmer and Art Deco architecture.[10] The city's population swelled in the 1960s and 1970s as refugees fled from civil war and American bombing during the Vietnam War. Phnom Penh's entire population was forcibly evacuated in 1975 by the Khmer Rouge, and faced persecution, forced labour and genocide. Phnom Penh remained largely uninhabited during the Democratic Kampuchea era until Vietnam-backed forces took the city in 1979. The city was reconstructed and infrastructure improved in the modern era with the support of international investment and aid. By 2019, it was home to more than 2 million people, approximately 14% of the Cambodian population.[4] The Greater Phnom Penh area includes the nearby Ta Khmau city and some districts of Kandal province.[11] The city formerly functioned as a processing center, with textiles, pharmaceuticals, machine manufacturing, and rice milling. It is also home to many prominent schools, colleges and universities. Its cultural institutions and events have made it a hub for domestic and international tourism.[12] The city has hosted numerous regional and international events, the most notable being the 2002, 2012, and 2022 ASEAN Summit, the 32nd Southeast Asian Games, and the 12th ASEAN

Para Games. Phnom Penh will be the first Cambodian city and the second city in Southeast Asia to host the Asian Youth Games in 2029.[13]