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An olla is a ceramic jar, often unglazed, used for cooking stews or soups, for the storage of water or dry foods, or for other purposes. Ollas have a short wide neck and a wider belly, resembling beanpots or handis.
- Main article: Olla (Roman pot).
The Latin word olla or aulla (also aula) meant a very similar type of pot in Ancient Roman pottery, used for cooking and storage as well as a funerary urn to hold the ashes from cremation of bodies. Later, in Celtic Gaul, the olla became a symbol of the god Sucellus, who reigned over agriculture.
American Southwest 
The Spanish settlers may have introduced the olla to Native American tribes, but it is likely they had developed a similar shape on their own. They often used unglazed pottery. The olla by its Spanish name has become associated with the region. It was used by settlers and natives both.
Among Southwestern Native American tribes, ollas used for storing water often were made with narrow necks to prevent evaporation in the desert heat. The olla is used by the Kwaaymii people, among many others, for cooking, storing water, serving meals and even nursing infants.
Use in irrigation 
Because water seeps through the walls of an unglazed olla, these vessels can be used to irrigate plants. The olla is buried in the ground next to the roots of the plant to be irrigated, with the neck of the olla extending above the soil. The olla is filled with water, which gradually seeps into the soil to water the roots of the plant. It is an efficient method, since no water is lost to evaporation or run-off.
This irrigation technique was introduced to the Americas by Spanish settlers in colonial times. Agriculture and gardening specialists are teaching it, and olla use is making a comeback in New Mexico and the American West. The state’s master gardening program is spreading the word. An olla factory has been founded in Albuquerque to produce the pots. It can be effective for homeowners to use in the desert climate. It has also been put to use by the Global Buckets project.
Use in refrigeration 
The olla is also useful for keeping water cool. When an unglazed olla is filled with water, the water permeates the clay walls of the vessel, causing the olla to “sweat”. The evaporation of the sweat cools the olla and its contents. In the early 20th century, many ranches in the American Southwest used the practice of hanging an olla from a rope on the verandah in a shady, breezy spot. Several hours after the olla was hung, it was cooled enough by evaporation to keep butter and milk safely cold.
As works of art 
In addition to utilitarian purposes, ollas are also produced by Native American and Mexican potters as artistic works. These ollas may be highly decorated and/or formed.
- "Kwaaymii Culture"
- "Spanish colonial olla irrigation makes a comeback", High Plains/Midwest AG Journal, 19 Apr 2005, accessed 8 Sep 2009
- "Ice Water From Sunshine", New York Times, 31 July 1910, accessed 31 Dec 2012