Karl Marx and Friedrich Engels wrote the Communist Manifesto in 1848 and were founders of the International Workingmen's Association.
Rosa Luxemburg was a leader of the German Social Democratic Federation and jailed for her opposition to World War I. She was assassinated in 1919.
Ernesto Che Guevara was born in Argentina and became a central leader of the Cuban Revolution. He was killed on a guerrilla mission in Bolivia in 1967.