International Women’s Day (IWD), originally called 
International Working Women’s Day, is marked on March 8 every year.[1]
The first national Women’s Day was observed on 28 February 1909 in the United States following a declaration by the Socialist Party of America.[2] In August 1910, an International Women’s Conference was organized to precede the general meeting of the Socialist Second International in Copenhagen. Inspired in part by the American socialists, German Socialist Luise Zietz proposed the establishment of an annual ‘International Woman’s Day’ (singular) and was seconded by Clara Zetkin, although no date was specified at that conference.[3] Delegates (100 women from 17 countries) agreed with the idea as a strategy to promote equal rights, including suffrage, for women.[4] The following year, on 18 March, 1911, IWD was marked for the first time, by over a million people in Austria, Denmark, Germany and Switzerland. In the Austro-Hungarian Empire alone, there were 300 demonstrations[3] In Vienna, women paraded on the Ringstrasse and carried banners honouring the martyrs of the Paris Commune.[3] Women demanded that women be given the right to vote and to hold public office. They also protested against employment sex discrimination.[2] Americans continued to celebrate National Women’s Day on the last sunday in February.[3]
In 1913 Russian women observed their first International Women’s Day on the last Sunday in February (by Julian calendar then used in Russia). In 1917 demonstrations marking International Women’s Day in St.Petersburg on the last Sunday in February (which fell on 8 March on the Gregorian calendar) initiated the February Revolution.[2]
Following the October Revolution, the Bolshevik Alexandra Kollontai persuaded Lenin to make it an official holiday in the Soviet Union, and it was established, but was a working day until 1965. On May 8, 1965 by the decree of the USSR Presidium of the Supreme Soviet International Women’s Day was declared a non working day in the USSR “in commemoration of the outstanding merits of Soviet women in communistic construction, in the defense of their Fatherland during the Great Patriotic War, in their heroism and selflessness at the front and in the rear, and also marking the great contribution of women to strengthening friendship between peoples, and the struggle for peace. But still, women’s day must be celebrated as are other holidays.”[citation needed]
In the West, International Women’s Day was first observed as a popular event after 1977 when the United Nations General Assembly invited member states to proclaim March 8 as the UN Day for Women’s Rights and International Peace.[5][1]
from Wikipedia.