Food & agriculture · c. 800 BCE

Qanat

Gently sloping tunnels tapped groundwater and carried it for kilometres without pumps.

Qanats were developed in Iran in the early first millennium BCE, bringing aquifer water to the surface by gravity with minimal evaporation. They spread across Persia, North Africa and Spain, and some still run today.

See it in the living tree Wikipedia

Arcs above join it to what it stood on, arcs below to what it led to. The bar places this stretch on the tree's whole timeline.

What it built on 1

Irrigation 6000 BCE

What it led to 1

Arab Agricultural Revolution 800

Related measurements

The dashed line marks when it first worked.

World population over a million years Latest: 6.27k million people (2000) Source: DeLong 1998, table 'Total World Population' (Kremer series); Kremer 1993, Population Growth and Technological Change: One Million B.C. to 1990, QJE 108(3)

Share of people living in cities Latest: 57.5 % (2025) Source: Our World in Data