Answer: People moved to cities to find a better job.
The "American dream" was influential in the development of large cities. People often migrated to cities looking for better jobs. Cities provided plenty of opportunities for workers, regardless of their origin or class. However, because of the large influx of immigrants, not all of them were able to improve their situation. Many immigrants were poor after moving to the city, which led to the development of segregated, low-income areas with high numbers of immigrants.
"The Articles of Confederation served as the written document that established the functions of the national government of the United States after it declared independence from Great Britain."