1835 Great Fire of 1835 destroys almost every building south of Wall Street and east of Broad Street. In subsequent decades, laws involing fire safety would help reduce fire risk in New York City buildings. 

1840s German Immigrants begin to settle in the Lower East Side and establish Kleindeutschland, or “Little Germany,” which becomes the second largest German speaking center in the world. At the same time, Irish Immigrants immigrate to New York to escape from the “Great Hunger.”