Adobe is mud that has been combined with tiny particles of plant material. When archaeologists excavate, they frequently come upon adobe. These images depict adobe fragments from two historic Pueblo dwellings. The imprints of the little branches and twigs that were part of the structure may still be seen. Adobes are soft when new and over time become hard and brittle. The word "adobe" comes from a Spanish term meaning "dry mud". This refers to how the mud is made up. Most adobe is made by mixing water with some type of soil (such as clay) and letting it dry in the sun or under shelters. When making bricks with adobe, only take out what you need and let the rest dry. Then, when you re-make your brick wall, you can use all of the previously dried adobe. People built their own homes out of adobe as early as 1000 AD. The Pueblo people used this building technique for many years after that. They would mix mud with straw or grass and then pack it into large mounds called pueblos. These would be used as shelter against the wind and rain. As the mud hardened under the sun or around a fire, more could be added, creating small rooms inside the main mound. After living in these pueblos for several years, the Pueblo people would move on and build themselves another home.