Mesopotamia

Mesopotamia is Greek for between the rivers, and the rivers are the Tigris and the Euphrates, which rise in the mountains of eastern Turkey and run southeast to the Persian Gulf. Most of it is modern Iraq, with pieces of northeastern Syria, southeastern Turkey, and the Iranian borderland. It is a historical region rather than a political one, and it is not a synonym for the Fertile Crescent, though the two get confused constantly: Mesopotamia is the eastern half of that larger arc, the flat, hot, irrigated half, while the Crescent also sweeps west through the Levant and, in some tellings, down the Nile. Sumer, Akkad, Babylon, and Assyria all grew out of this floodplain.

The land is an alluvial plain, built grain by grain from silt the two rivers carried down off the Taurus and the Zagros across millions of years, and it is nearly flat: Baghdad stands about 34 meters above the sea. Rain is too scarce for farming, so everything depended on the annual floods and on the canals that spread them, an engineering project that had to be organized, which is one reason states appeared here first. The basin drains roughly 880,000 square kilometers, and its rim climbs to 4,135 meters at Cilo Dag, in the Tigris headwaters. In the south the two rivers merge into the Shatt al-Arab and dissolve into the marshes of the Ahwar.

Between roughly 4000 and 3000 BCE the people of Sumer built the first true cities, Uruk, Ur, Eridu, and invented cuneiform writing to keep track of grain and debt, leaving the earliest literature, including the Epic of Gilgamesh. The wheel, the sexagesimal arithmetic that still governs our clocks, the first written law codes, and the first empires all trace to this ground. Salinization from millennia of irrigation slowly poisoned the southern fields, and the rivers have wandered from their old beds. The region now carries the burdens of modern Iraq: upstream dams in Turkey and Iran, drought, war damage, and the deliberate draining of the marshes under Saddam Hussein, only partly reversed.