A subterranean or semi-subterranean dwelling found in the American southwest; the earliest manmade dwellings. It usually had an underground floor and aboveground earthen or brush walls supported by interior posts and was the primary habitation structure of individual families of basketweaving cultures. These structures may be round, oval, or square to rectangular, but usually have a straight entrance. Most were roofed with thatch and supported by posts. Often, all that remains on an archaeological site is a large, shallow pit. Its most popular period was 200-900 AD and it evolved into the kiva.