Diamond notes that modern technologies and institutions were designed primarily in a small area of northwestern Europe. After the Scientific Revolution in Europe in the 16th century, the quality of life increased and wealth began to spread to the middle class. This included agricultural techniques, machines, and medicines. These technologies and models readily spread to areas colonized by Europe which happened to be of similar climate, such as North America and Australia. As these areas also became centres of innovation, this bias was further enhanced. Technologies from automobiles to power lines are more often designed for colder and drier regions, since most of their customers are from these regions.