"Rosa Luxemburg, brave woman Socialist of Germany, who was later brutally murdered by the militarists, sounded the alarm against a World War in 1913. She called upon the workers to make May Day a mighty demonstration for peace and socialism. “Workers of the world, Unite!” became the insistent cry on May Day. Every vital issue was pressed, more and more militant slogans raised in each country and internationally."
January 1, 1970
https://en.wikiquote.org/wiki/Rosa_Luxemburg