During the 19th century, the United States experienced many changes. Technology started to advance and it caused a huge economic boom. Many immigrants from all over the world came to the United States because there were so many job opportunities. Later the Americans didn’t like the immigrants from these coming from Mexico, Europe, and Asia. Because Mexico was adjacent to United States, Mexican immigrants came to the United States to settle there. The effects after the Mexican Revolution, World War I, and the Immigrant Acts of the 1920s caused many problems and tension between Mexico and the United States. This led to nativism and made people developed xenophobia.