Women take part in a march to mark International Women's Day in Mexico City on March 8. On March 8 activists around the globe celebrate International Women's Day, which dates back to the beginning of the 20th Century and has been observed by the United Nations since 1975. The UN writes that it is an occasion to commemorate achievements in women's rights and to call for further change. The writing on the women's backs read (L-R), "It is now when we assume our historical role", "I am one of thousands of women fighting", and "Not submissive, not devoted. Combative women". Reuters/Edgard Garrido