Around 3000 BC, the Tigris and Euphrates rivers flooded the low-lying plains of southern Mesopotamia and created something new. The marshes that formed were not stagnant pools but a flowing system, fed by the Al-Musharrah and Al-Kahla branches of the Tigris on the Iraqi side and the Karkheh River on the Iranian side, drained by the Al-Kassarah River that prevents the basin from turning saline. This hydrology sustained an ecosystem rich with fish, migratory birds, and dense reed beds. The Sumerians and Babylonians who lived along these waterways built the earliest known civilizations amid the marshes' bounty. Five millennia later, the basic pattern of life persists. The Marsh Arabs of Iraq and the Hawizeh people of Iran still fish, hunt, and herd buffalo in these waters, still build reed houses without electricity, still travel by mashoof through channels that ignore the international border.

In the early 1990s, Saddam Hussein's government began systematically draining the Mesopotamian Marshes. The official justification was to flush out armed opposition groups believed to be hiding in the wetlands. The real effect was the displacement of more than 200,000 Marsh Arabs, a campaign of environmental destruction so targeted that the United States and international observers described it as ecocide. Canals were dug to divert the Tigris and Euphrates away from the marshlands. The Central Marshes and the Hammar Marshes dried almost completely, their beds cracking into salt-crusted desert. The Hawizeh survived. Its position straddling the Iranian border, beyond the full reach of Iraqi engineering projects, kept enough water flowing to prevent total desiccation. It became the last refuge for species that had vanished from the drained marshes, a biological ark holding the genetic diversity that any future restoration would depend upon.

The marsh communities exist in a kind of parallel world. No hard border separates the Iraqi and Iranian sides of the Hawizeh. Families paddle mashoofs between countries as casually as crossing a street. The cities they built sit on water, clusters of reed structures that have no use for roads or automobiles. Religious life blends ancient Sumerian traditions with Shia Islam and, in some communities, the older Mandaean faith. Stories circulate through the marshes that mix Islamic teaching with far older Mesopotamian mythology, tales of spirits and curses rooted in landscapes that have barely changed since the age of Gilgamesh. This isolation preserved the culture but also left it vulnerable. Most marsh communities have limited access to education or modern infrastructure. The simplicity that outsiders romanticize is also deprivation that residents navigate daily.

After the 2003 Iraq War, the new government reopened water flows to the drained marshes. Water returned to the Central and Hammar marshes, and displaced communities began filtering back. In 2007, Iraq became a signatory to the Ramsar Convention, and the Hawizeh Marshes were designated a wetland of international importance. Recovery, though, has been uneven. Oil exploration in the region now threatens the ecosystem from a different direction. Drilling operations and associated infrastructure have drained portions of the wetland, and power cables strung across the marshes kill migratory birds. The Hawizeh survived a dictator's attempt to erase it. Whether it survives the slower, quieter pressures of petroleum development is the question that defines its future. Roughly 5,000 people have returned to live in the marshes. They are rebuilding a way of life that is 5,000 years old, in a landscape that the modern world keeps finding new reasons to transform.