Scientific progress has therefore been reflected in the design of buildings. Most inhabitants of ancient Egypt lived in huts built of mud bricks constructed from the rich silt of the Nile, while in Europe and the Far East people used the plentiful supplies of timber to build their houses. Even today the majority of the world's population lives in homes built from material available from their local environment (Figure 3.1). Yet as science developed and the understanding of the properties of materials grew, we have begun to fashion our own materials (e.g. concrete and glass) which can be used to construct stronger, warmer and more pleasant homes. Thus, from the natural environment we have gradually fashioned across the world a new environment in which we live, the built environment.