Vietnam. Vietnam, officially the Socialist Republic of Vietnam, is a country at the eastern edge of mainland Southeast Asia, with an area of about 331,000 square kilometres (128,000 sq mi) and a population of over 100 million, making it the world's fifteenth-most populous country. One of the two Marxist???Leninist states in Southeast Asia, Vietnam shares land borders with China to the north, and Laos and Cambodia to the west. It shares maritime borders with Thailand through the Gulf of Thailand, and the Philippines, Indonesia, and Malaysia through the South China Sea. Its capital is Hanoi and its largest city is Ho Chi Minh City (commonly known as Saigon). Vietnam was inhabited by the Paleolithic age, with states established in the first millennium BC on the Red River Delta in modern-day northern Vietnam. The Han dynasty annexed Northern and Central Vietnam, which were subsequently under Chinese rule from 111 BC until the first dynasty emerged...