Qanat
A qanat is a series of well-like holes and tunnels dug to reach a natural underground source of water, usually run-off from a mountain. They were (and are) used to provide water in the desert regions of the Middle East. The oldest qanats, found in the region once known as Persia (now known as Iran), are believed to be a couple of thousand years old.
Qanat Media
Qanat in Kashan surfacing within the Fin Garden; it is thought to have served Iran's Sialk area for thousands of years.
A kariz surfacing in Niavaran, Tehran, currently used for watering the grounds of The National Library of Iran
Possible diffusion of qanat technology
Alluvial fan in southern Iran. Image from NASA's Terra satellite.
Wind tower and qanat used for cooling
A Persian Ab anbar with wind towers connected to a qanat
Water "metering" through a distribution weir on a foggara in Algeria
