The United Nations observes designated days, weeks, years, and decades, each with a theme, or topic. By creating special observances, the United Nations promotes international awareness and action on these issues. The majority of observances have been established by resolutions of the United Nations General Assembly, although some have been designated by UN specialized agencies. The United Nations also observes anniversaries of key events in its history.
UN Day marks the anniversary of the entry into force in 1945 of the UN Charter. With the ratification of this founding document by the majority of its signatories, including the five permanent members of the Security Council, the United Nations officially came into being.
24 October has been celebrated as United Nations Day since 1948. In 1971, the United Nations General Assembly recommended that the day be observed by Member States as a public holiday.