United Nations Day for South-South Cooperation is observed worldwide on September 12. This observance was officially established in December 2003 and originally took place on December 19 until the date was moved in 2011. The day commemorates the adoption of the Buenos Aires Plan of Action for Promoting and Implementing Technical Cooperation among Developing Countries in 1978. South-South cooperation refers to the exchange of knowledge, technology, and resources among developing countries in Africa, Latin America, and Asia. It aims to reduce the dependence of these countries on assistance from developed nations, serving as a complement to North-South cooperation. The UN Unit for South-South Cooperation, established in 1978, plays a significant role in promoting these collaborative efforts.