Vietnam, officially the Socialist Republic of Vietnam, is the easternmost country on the Indochina Peninsula in Southeast Asia. With an estimated 92.7 million inhabitants as of 2016, it is the world's 14th-most-populous country and the ninth-most-populous Asian country. Vietnam is bordered by China to the north, Laos to the north-west, Cambodia to the south-west, Thailand across the Gulf of Thailand to the south-west, and the Philippines, Malaysia and Indonesia across the South China Sea to the east and south-east.Its capital city has been Hanoi since the reunification of North and South Vietnam in 1976. Vietnam was part of Imperial China for over a millennium, from 111 BC to AD 939.
An independent Vietnamese state was formed in 939, following a Vietnamese victory in the Battle of Bạch Đằng River. Successive Vietnamese imperial dynasties flourished as the nation expanded geographically and politically into Southeast Asia until the Indochina Peninsula was colonised by the French in the mid-19th century. Following a Japanese occupation in the 1940s, the Vietnamese fought French rule in the First Indochina War, eventually expelling the French in 1954. Thereafter, Vietnam was divided politically into two rival states, North and South Vietnam. The conflict between the two sides intensified in what is known as the Vietnam War. The war ended with a North Vietnamese victory in 1975.