If one thing characterized early 20th century cities, it was their immigrant character. The “new immigration” from southern and eastern Europe had begun around 1890 but reached its peak during the Progressive era. Between 1901 and the outbreak of World War I in Europe in 1914, some 13 million immigrants came to the United States, the majority from Italy, Russia, and the Austro-Hungarian Empire.” One of the legacies of the immigrant experience is the formation of distinctive ethnic neighborhoods. Ethnic enclaves are specific parts of cities where ethnic minorities live. In these areas the people living there would create religious and cultural organizations where residents of the same ethnic groups could form communities. However, housing and infrastructure became a major issue. As urban populations increased, new types of housing were developed. Sometimes, two or three families occupied a single family home. These multifamily urban dwellings, called tenements, were overcrowded and unsanitary. Cities tried to keep up with the growth and expansion of the population, but usually failed, resulting in poor living conditions for immigrants.