In which John Green teaches you about the massive immigration to the United States during the late 19th and early 20th century. Immigrants flocked to the US from all over the world in this time period. Millions of Europeans moved to the US where they drove the growth of cities and manned the rapid industrialization that was taking place. In the western US many, many Chinese immigrants arrived to work on the railroad and in mines. As is often the case in the United States, the people who already lived in the US reacted kind of badly to this flood of immigrants. Some legislators tried to stem the flow of new arrivals, with mixed success. Grover Cleveland vetoed a general ban on immigration, but the leadership at the time did manage to get together to pass and anti-Chinese immigration law.