“You can never step in the same river twice”, as the saying goes. Asia’s third longest watercourse (after the Yangtze and Yellow rivers of China), the Mekong, which originates in the Tibetan plateau at an elevation of 5500m, changes dramatically as it winds it way down through six nations to empty in the East Sea. I have never followed the entire length of this great river, although I have visited many portions of it at different times.