Chronoways by city

1886. World-wide. May Day or International Workers' Day.

May Day has been set aside to commemorate the labor movement in many countries around the world. An international workers’ day was first called for in 1889 at the Second International, a meeting of socialists in Paris, France. The day was intended to honor anarchist workers who were sentenced to death following the Haymarket Square Riot in 1886 in Chicago, Illinois.

Web: Encarta Encyclopedia

1810. Buenos Aires (Argentine). Viceroyalty of the Río de la Plata. May Revolution.

Web: Wikipedia

1816. Argentine. Argentine Declaration of Independence.

The Independence of Argentine was declared on July 9, 1816 by the Congress of Tucumán.

Web: Wikipedia

1945. Buenos Aires (Argentine). Loyalty Day.

Loyalty Day as is known in Argentina for the annual commemoration of October 17, 1945, when he was in Buenos Aires a massive workers' union to demand the release of Colonel Juan Domingo Peron, was arrested by the military government that was part of the secretary of Labor.

Web: Wikipedia (spanish)