A qanāt (Persian: قَنَات) or kārīz (کَارِیز) is a water supply system that was developed in ancient Iran for the purpose of transporting usable water to the surface from an aquifer or a well through an underground aqueduct. Originating approximately 3,000 years ago, its function is essentially the same in systems across Asia and North Africa, but it is known by a variety of regional names beyond modern Iran, including: kārēz in Afghanistan and Pakistan; foggāra in Algeria; khettāra in the Atlas Mountains; the daoudi-type falaj in Oman and the United Arab Emirates; and ʿuyūn in Saudi Arabia. In addition to those in Iran, the largest extant and functional qanats are located in Afghanistan, Xinjiang in China (the Turpan water system), Oman, and Pakistan.