Pueblos are an example of passive design in vernacular architecture. Pueblos are the traditional architectural style of the Ancestral Pueblo people, whom are indigenous to what we now call the southwestern United States.
The Ancestral Pueblo people designed and built their pueblos with passive design strategies long before that term was coined.
Pueblos are often built on an east-west orientation, facing south to maximize light and heat from the sun. Pueblos are built of limestone blocks or adobe bricks, which have the thermal mass to insulate against large daily and seasonal temperature swings. For example, in the winter, pueblo walls will retain heat from the sun, slowly releasing the heat throughout the night. In the summer, the opposite is true: pueblo walls cool down at night, and if kept shaded will remain cool enough to keep a stable temperature inside during the day.