Title?
From 1845-1855 one million immigrated to the United States.
They immigrated partially to escape economic hardship.
They also immigrated partially to escape political unrest that included riots, rebellions, and a revolution in 1848.
America was one of the few countries in the world that would accept their immigration.
A good title for the above list would be —
German Immigrants
Irish Immigrants
African Immigrants
Chinese Immigrants