Contributor Ali Webb takes a journey on the Mekong River from Saigon to Siem Reap in southeast Asia. In the heart of Southeast Asia, the winding Mekong River carries more than just water.

The Journey Begins: China's Yunnan Province marks the beginning of the journey of the Mekong River, the waters that flow through the heart of Southeast Asia. (S1, ... Thailand - The River Basin: ...