In some areas, most people build their homes out of wood.
This is true in parts of North America and in Scandinavia.
These areas have large forests, so wood is easy to get and inexpensive.
In many other areas of Europe, there are few forests left.
Stone and brick are cheaper, so most people build their houses of these materials.
In tropical regions, houses are sometime made from plants that grow there.
For example, in parts of Africa or Asia, houses may be made out of bamboo.