Thu Bồn River

This guide to the Thu Bồn River in Hoi An opens at a wooden column in a merchant's house, marked with every flood since 1964, the year the water reached a height that stood unmatched for six decades. It follows the river two hundred kilometers back to the Truong Son mountains near the Laotian border, tracing how its regular seasonal floods built the fertile plains of Quang Nam while slowly silting in the old harbor that once made Hoi An a trading port. Look at the buildings around you and guess how high those old marks would run above your head.