Prehistoric people lived in caves. The first houses were rough shelters, made if mud, branches and leaves. Later, people learned how to make bricks by drying wet clay in the sun. Brick, wood and stone were for thousands of years the materials from which almost all houses were built.
The modern house is built to keep out the cold and wet, and to keep in warmth. Double glazing of windows and insulation in the roof and walls help to do this. Many homes have central heating and, in hot climates, air conditioning.
In most countries a house is lived in by either a single family or a family group. A number of houses joined together form a terrace. Two houses joined side by side are semi-detached. A number of homes built on top of one another form a block of flats or apartments. In many big cities, there are not enough houses to provide homes for everybody. In some countries, poor people have to live in slums and shanty towns.
Although houses in cities around the world look very much the same, there are still lots of differences in the way houses are build. Houses in North Africa and Arabia, for example, have thick mud brick or cement walls and small windows. This help to keep them cool.
In South East Asia, many people live in houses built on stilts over the water. In Borneo, a whole village may live in one big dwelling called a long-house. In Canada, the USA and Scandinavia many houses are built of wood, whereas in parts of Britain you will see houses made of local stone, perhaps with a roof of thatch (reeds).
Houses are built differently from flats. Both must have foundations, with pipes for water and sewage, and cables for electricity laid on. A house often has walls of brick, covered on the inside with plaster. The floors are made of concrete or wood. The roof is usually sloped, so that rain runs of easily, and is covered with rows of running slates or tiles a block of flats has a framework of steel girders to give extra strength. The walls may be factory-made panels, lifted into place by a crane. It will have a lift as well as stairs, and it may well have a flat roof.
