The United Nations has declared 92 International Days, 7 International Weeks, 58 International Years, and 35 International Decades. These Observances serve to focus the world on key issues and ideals. Below is an official description and link to the United Nations Observances website:
United Nations observances are used to contribute to the achievement of the purposes of the UN Charter and promote awareness of and action upon, important political, social, cultural, humanitarian or human rights issues. They provide a useful means for the promotion of international and national action and stimulate interest in United Nations activities and programmes. For international years and decades the UN Secretary General takes action to establish preparatory process, evaluation and follow-up procedures.
The majority of observances have been established by the UN General Assembly and some have been designated by UN specialized agencies.
In 1950, the General Assembly approved the first international day “Human Rights Day” to be observed on 10 December. Resolution 423 (V) invited all states and international organizations to observe this day to celebrate the proclamation of the Universal Declaration of Human Rights by the General Assembly on 10 December 1948, and to exert increasing efforts in this field of human progress.
In 1978, the General Assembly by its resolution S-10/2 proclaimed the first international week—the week starting 24 October (the day of the foundation of the UN)—as a week devoted to fostering the objectives of disarmament (Disarmament Week).
The first international year was proclaimed by the General Assembly in 1959. It was the World Refugee Year [Resolution 1285 (XIII)].
The first UN decade was the United Nations Development Decade designated by the General Assembly in 1961 [Resolution 1710 (XVI)].
Every year the United Nations Department of Public Information issues a press release United Nations Conferences and Observances that contains a list and description of all the events for current and ensuing years.