Chàm Islands

This guide to the Chàm Islands off Hoi An follows the birds that make its cave walls worth a fortune: swiftlets that glue nests to bare stone using nothing but saliva, navigating pitch-black caves by echolocation like bats. You'll hear the local legend of Nang Yen, a shipwrecked woman said to have copied the birds out of hunger, and meet the families of Thanh Chau village who still climb these cliffs on hand-lashed bamboo scaffolding each spring and summer. Look up at the dark cave mouths above you and imagine the colonies hidden inside, never touched by artificial light.