The qanat (called foggara in North Africa and the Levant, falaj in the United Arab Emirates and Oman, kariz in Iran, and puquios in Peru) is an ancient Middle Eastern irrigation technique in which a long tunnel is dug into arid land that allows water from underground aquifers to be accessed for use by the local population, supporting large settlements in spite of hostile environmental conditions. Qanats begin as deep wells dug into elevated land and culminate in streams flowing through outlets into a human settlement. Outflows sustain settlements by providing water for crops and drinking water for the population. Powered only by gravity, these simple wonders of ancient architecture allowed settlements in arid climates to have dependable access to water, sometimes for centuries at a time. Today, tens of thousands of qanats still function in around 35 countries across the globe.
This is a companion discussion topic for the original content at https://www.worldhistory.org/qanat/.