In Laos's deepest south, just above the border with Cambodia, the muddy stream of the Mekong is carved into a fourteen-kilometre-wide web of rivulets, creating a landlocked archipelago.

Known as Si Phan Don, or "Four Thousand Islands", this labyrinth of islets, rocks and sandbars has acted as a kind of bell jar, preserving traditional southern lowland Lao culture from outside influences. The largest of the permanent islands are inhabited year round and offer fascinating glimpses of tranquil river-oriented village life – ‘more detached from time than from the riverbank’ as one source described it. Communities tend to be self-sufficient, growing most of their own rice, sugar cane, coconut and vegetables, catching fish and weaving textiles as needed. The archipelago is home to rare flora and fauna, including a species of freshwater dolphin. Southeast Asia's largest waterfalls are also located here.