International Museum Day has been held around the 18th of May every year since 1977.It was started by the International Council of Museums (ICOM).ICOM says: “The event provides the opportunity for museum professionals to meet the public and alert them to the challenges that museums face.”It wants the public to know museums are “an institution in the service of society and of its development".ICOM encourages its member countries to celebrate the day in a way that is best for their specific cultures.It asks countries to follow its simple motto: “Museums are an important means of cultural exchange, enrichment of cultures and development of mutual understanding, co-operation and peace among peoples.”Museums are an important part of every society.They are a great source of education and wonder.The UK Museums Association says a museum is: “A permanent institution in the service of society.”It says a museum “acquires, conserves, researches, communicates and exhibits the heritage of humanity”.It adds that museums are for “the purposes of education, study, and enjoyment”.There are museums on just about anything you can think of.