International Women’s Day began as National Women’s Day in the US in 1909 and has its roots in the now defunct Socialist Party of America. The following year, a German woman named Clara Zetkin proposed the first International Women’s Day while at the second International Conference of Working Women, held in Copenhagen. The day was first celebrated internationally in 1911 and has been observed in many countries every year since then. It was moved from its original date in late February to its current date, March 8, in 1913.
The United Nations began honoring International Women's Day in 1975, the UN-proclaimed International Women's Year. In 1977, it went a step further, adopting a resolution recognizing International Women’s Day. Since its first celebration, the UN has hosted four international women's conferences and in 2010, it created the UN Entity for Gender Equality and Empowerment of Women – also known as UN Women.