The Second International, which was an international organization of political parties, led to the founding of the Socialist International.
In 1889 they declared May 1 as International Labour Day. A day that began in the US. And in 1910 they declared March 8 as International Women's Day. Some nice facts.
A side note - in 1980 the National Chicano Moratorium Committee, Union del Barrio, and Partido Nacional La Raza Unida declared August 29 - Raza Memorial Day, honoring those who died for Chicana and Chicano freedom and liberation.