United Nations Day
This is a past event
On October 24, 1945, the United Nations (UN) came into force when the five permanent members of the security council ratified the charter that had been drawn up earlier that year. These members were: France, the Republic of China, the Soviet Union, the United Kingdom and the United States.
Since 1948, the event's anniversary has been known as United Nations Day. It is an occasion to highlight, celebrate and reflect on the work of the United Nations and its family of specialized agencies.
http://www.timeanddate.com/holidays/un/united-nations-day