Hundreds of Ancestral Puebloan dwellings are found across the American Southwest. With almost all constructed well before , these Puebloan towns and villages are located throughout the geography of the Southwest. Many of these dwellings included various defensive positions, like the high steep mesas such as at the ancient Mesa Verde complex or the present-day Acoma "Sky City" Pueblo. Earlier than progressing past the 13th century, the population complexes appear to have been major cultural centers for the Pueblo peoples. There were also settlements scattered throughout the region of varying sizes. Cultures Ancestral cultures Ancestral Puebloans spanned Northern Arizona and New Mexico, Southern Colorado and Utah, and a part of Southeastern Nevada. They primarily lived north of the Patayan, Sinagua, Hohokam, Trincheras, Mogollon, and Casas Grandes cultures of the Southwest and south of the Fremont culture of the Great Basin . Contemporary cultures There are 21 federally recognized pueblos in the United States today. Rio Grande pueblos are known as eastern Pueblos; Zuni, Hopi, and sometimes Acoma and Laguna are known as western Pueblos. Geography The dwellings of the Pueblo peoples are located throughout the American Southwest and north central Mexico. The American states of New Mexico, Texas, Colorado, Utah, Nevada, and Arizona all have evidence of Pueblo peoples' dwellings; the Mexican states of Chihuahua and Sonora do as well. Eras Archaeologists have agreed on three main periods of ancient occupation by Pueblo peoples throughout the Southwest called Pueblo I, Pueblo II, and Pueblo III. Pueblo I (). Pueblo buildings were built with stone, windows facing south, and in U, E and L shapes. The buildings were located more closely together and reflected deepening religious celebration. Towers were built near kivas and likely used for look-outs. Pottery became more versatile, not just for cooking, but now included pitchers, ladles, bowls, jars and dishware for food and drink. White pottery with black designs emerged, the pigments coming from plants. Water management and conservation techniques, including the use of reservoirs and silt-retaining dams also emerged during this period. Midway through this period, about , the number of Hovenweep residential sites increased. Pueblo II (). During the Pueblo II period there was an increase in population that resulted in creation of more than 10,000 sites in 150 years. Since much of the land was arid, the people supplemented their diet by hunting, foraging and trading pottery for food. By the end of the