The Pueblo are Native Americans in the Southwestern United States who share a common Southwestern culture. The Puebloans are descended from the ancient Anasazi, who emerged around the 12th century BC. When the Spanish arrived in the region in the 16th century, they came across adobe houses which they called pueblos, a term that came to represent the people of the villages. Pueblo communities are located in New Mexico, Arizona, and Texas, living along the Rio Grande and Colorado rivers and tributaries. The Puebloans developed a syncretic approach to Catholicism during Spanish rule, and they are organized into families and clans with old traditions. By the 21st century, 35,000 Puebloans lived in New Mexico and Arizona.