In this lesson you will examine how spatial diffusion occurs as a result of a phenomenon. The phenomenon to be examined is immigration. From 1800-1924 there was a great migration of Europeans to the United States. The reasons for this large number of immigrants coming to the United States included: overpopulation, land shortage, and unemployment, all were conditions that created severe economic burdens in Europe. These conditions, along with legalized religious persecution, caused many Europeans to decide to immigrate to the United States in search of better economic opportunities.