I'm not sure why my wall calendar (produced by a Canadian environmental organization) reminds me that today is Cinco de Mayo. Also up this month: World Press Freedom Day, Mother's Day, International Migratory Bird Day, International Day of Families, International Day for Biological Diversity, Victoria Day, and Memorial Day (US).
We don't celebrate Mother's Day in this country; we celebrate Mothering Sunday (even though the cards all say "Happy Mother's Day"), and it is exactly three weeks before Easter. We don't celebrate VE day in Britain, but the liberation Day is a public holiday in the Channel Islands. Only it's (I think) 8th May.