March 8 is acknowledged by the UN as International Women's Day (from now on referred to as IWD). The day has a long history, and is recognized in many countries, many of which mark the day as a national holiday. Equal rights for women is one of the main points of the Charter of the United Nations, signed in San Francisco in 1945.

According to UN's official webpages (www.un.org), the idea of a Women's Day springs out of the social change going on around the turn of the last century. The Socialist Party of America declared a National Woman's Day, which was celebrated in the US the first time on February 28, 1909. The last Sunday of February was used for this through 1913.

Inspired by the American women, the German socialist Klara Zetkin organized the first IWD on March 19, 1911. Such an event was also proposed by the Socialist international meeting in Copenhagen the year before. More than a million women and men rallied in Austria, Denmark, Germany and Switzerland, demanding suffrage for women, the right to work and an end to discrimination.

The date March 8 was picked in 1917, when Russian women used the IWD as a major strike, to protest against the war. Rallying for "bread and peace" in St. Petersburg, the strike led to riots that had a direct impact on the Czar's abdication four days later (see Russian February Revolution of 1917). The date chosen for this strike was the last Sunday of February (February 23) on the Julian calender used in Russia, March 8 on the Gregorian calender used in "the West".

The celebrations of IWD dwindled after the 1920s, but was revived as part of the women movement in the 1960s. It became officially sponsored by the UN in 1975.

Note: This was issued to me as a Nodeshell Challenge by NothingLasts4ever after I made the nodeshell myself...

Sources:
http://www.un.org/ecosocdev/geninfo/women/womday97.htm
http://www.infoplease.com/spot/womensday1.html