One of the world's great rivers. It is the world's 10th-longest river and the 7th-longest in Asia. Rising in southern Qinghai province, China, it flows south through eastern Tibet and across the highlands of Yunnan province. It then forms part of the border between Myanmar (Burma) and Laos, as well as between Laos and Thailand. It runs through Laos and Cambodia before entering the South China Sea in a delta south of Ho Chi Minh City in Vietnam Its estimated length is 4,909 km (3,050 mi), and it drains an area of 795,000 km2 (307,000 sq mi), discharging 475 km3 (114 cu mi) of water annually.