Crime of ages was The assasination of Ferdinand.
The Underground Railroad wasn't a real railroad, but a network of courageous people who helped slaves secretly travel from the South to the North. In 1850, President Fillmore signed the Fugitive Slave Act, which made it illegal to help a slave run away and required officials to return escaped slaves to their owners.
It was the "c. introduction of the assembly line" that enabled mass production in the 1920s, since this meant that products could be made with a division of labor.
