This document provides information about urbanization in the United States during the late 19th and early 20th centuries. It discusses the growth of large cities like Manchester, England and Chicago due to industrialization and rural-to-urban migration of workers. It also describes some of the problems that arose in cities like overcrowding, poor living conditions in tenement housing, lack of sanitation and infrastructure, and public health issues. The document outlines some technological innovations that helped modernize cities and address problems like skyscrapers, elevators, electric streetcars, and subways.