The document discusses New York City's history as a center of world trade and immigration in the late 19th and early 20th centuries. It notes that by 1860 over a million people lived in New York, the greatest number of rich and poor living together in one area in history. The Great Depression hit New York hard, with thousands protesting and Hoovervilles appearing in Central Park. The document also discusses the massive transatlantic migration from 1870-1914 that saw over 23 million immigrants enter the US, predominantly from Europe and settling in large numbers in New York City.