Sue Perkins embarks on a life-changing, 3,000-mile journey up the Mekong, South East Asia's greatest river, exploring lives and landscapes on the point of dramatic change.

Despite its critical role in modern society, the environmental and social effects of sand mining remain largely hidden from public scrutiny.

Running the length of the mainly mountainous country is the mighty Mekong River, which floods rice fields, creates vital fish habitat, and serves as the main highway and water source. Villages ...