Mekong

— The Mekong River’s lower basin is vast, encompassing parts of Myanmar and Thailand, virtually all of Laos and Cambodia and parts of southern Vietnam, where, after a 3,000-mile journey across five national borders, the mother of rivers divaricates into a complex delta network and drains into the South China Sea. Tonle Sap Lake sits roughly in the middle of this lush expanse. On a map, it appears as a crooked blue finger extending from the Mekong near Phnom Penh. But it is more often described as Cambodia’s heart, both for its rhythmic flood pulse and the sustaining role it plays in the country’s economy and food supply.