One of the world's great rivers rises in the mountains of Tibet and flows southeastward into the South China Sea in Vietnam. What river is it?

This mighty river begins its epic 2,700-mile journey as the Lancang on the high Tibetan Plateau in China. From there, it carves a path southeastward, flowing through or forming the borders of Myanmar, Laos, Thailand, and Cambodia. This transnational journey, which gives the river many different local names, is the geographical basis for its reputation as one of the world's most significant waterways.

The river's journey culminates in southern Vietnam, where it slows and fans out into the immense, fertile Mekong Delta. This "rice bowl" of Vietnam is a testament to the river's life-giving power, supporting millions of people through agriculture and fishing. Finally, after nourishing six different nations, its waters empty into the South China Sea. Its basin is a global hotspot of biodiversity, second only to the Amazon, making it a vital resource both culturally and ecologically for all of Southeast Asia.