Side by side: Rosa Luxemburg (at right) in April 1915 with women's rights advocate Clara Zetkin (1857–1933). Zetkin organized the first International Women's Day in 1911. It has been celebrated on March 8 around the world for well over a century.

Side by side: Rosa Luxemburg (at right) in April 1915 with women's rights advocate Clara Zetkin (1857–1933). Zetkin organized the first International Women's Day in 1911. It has been celebrated on March 8 around the world for well over a century.

Bildquelle: picture alliance / CPA Media Co. Ltd.