In the 1920s, America witnessed a modern urban explosion. More than ever before, new cities began to come to life and attract an enormous number of immigrant laborers and Southern farmers seeking a more adventurous life in the American North. Certain historians consider the urban pull of immigrant labor to be one of the most powerful shaping forces in American history. Very quickly, many northern cities began to incorporate the addition of "little" cities to their retinue: "Little Italy" in New York and Chicago, "Little Hungary" in Philadelphia, Chinatowns all over the US, and so on. These immigrant enclaves were augmented by the influx of African Americans coming from the South.
The influx of primarily black urban laborers looking for manufacturing jobs corresponded with a significant rise in black subcultures in the inner cities and neighborhoods. This period of black cultural revival, particularly in New York City, is known as the Harlem Renaissance, and it saw a large number of African American socialites, intellectuals, musicians, writers, and artists begin to express their unique contributions to American urban culture. Some of the most famous people associated with this movement include short story authors like Langston Hughes, nationalist leaders of the "New Negro" movement such as Marcus Garvey, and musicians like Dizzy Gillespie, Duke Ellington, and Louis Armstrong. The period is often referred to as the Jazz Age because jazz music emerged as a new form of artistic expression and served as a symbol of new forms of recreation and sexuality.