1) New York City saw large waves of Irish and African American immigration in the 1800s, with the Irish population experiencing much higher death rates than other groups due to poor living conditions.
2) In the 1920s, New York City's economy boomed during the "second industrial revolution" as consumer goods became widely available through mass production.
3) Figures like P.T. Barnum helped grow New York City's culture and entertainment industry in the 1800s with attractions that blended museums, performances, and exhibitions.