Urbanization occurs when people leave rural areas to move to urban centers. It is a demographic trend that happens when societies industrialize since factories are built in urban areas. Industrialists take advantage of the technology, rivers, transportation networks and infrastructure found in urban areas. The larger populations in urban areas provide labor for the factories as well.
In the 18th Century, however, industrial growth outpaced the populations found in the urban areas. This sparked a high demand for labor which was met by people moving in from rural areas. The mechanization of agricultural tools meant that a smaller amount of workers was needed on the farms to produce the same amount or more of farm goods. For this reason, the demand for farm workers was on the decline in rural areas at the same time demand for unskilled labor in the urban factories was skyrocketing.