Pueblo people lived in multi-story adobe dwellings known as pueblos, which are composed of adobe (clay and straw baked into firm bricks) and stone. Like a modern apartment, each adobe unit housed a single family. The floors would be covered with rugs or mats of grass or wood. Adobe buildings are strong and can stand up to harsh weather conditions. They use very little material to build with, which makes them affordable to use. In addition, the processes used to make adobe brick are simple and easy to learn, which means that almost anyone can do it. This is one reason why many early American settlements were built in adobe style. There are several different types of pueblos. The most common type is called a "town plaza" pueblo because it has a central square or plaza that is used for public gatherings and ceremonies. Each side of the plaza is bordered by an alleyway called a calle. The alleys provide access to the various structures on each floor. The top floor usually has only one structure since there's no room for more than one room on this level. The town plaza pueblo was the most common type in New Mexico before the arrival of Europeans. These days, they're mostly found in northern New Mexico at sites such as Santa Fe, Taos, and Zuni.