In 2001, UNESCO adopted the Universal Declaration on Cultural Diversity and in December 2002, the UN General Assembly, in its resolution 57/249, declared May 21 as the World Day for Cultural Diversity for Dialogue and Development. The day provides an opportunity to deepen understanding of the values of cultural diversity and for people to learn to live together better.
http://www.newvision.co.ug/news/668708-world-day-for-cultural-diversity.html