International Museum Day is observed worldwide every May 18. Established in 1977 by the International Council of Museums, this event celebrates the role of museums in society and promotes the protection of cultural and natural heritage. Each year, the council selects a specific theme and sponsors contests to encourage public engagement with museums. The holiday has gained significant attention over the years, with participation from 30,000 museums across 129 countries as of 2012. The official poster for International Museum Day has been translated into 38 languages, reflecting its global reach and impact.