May 3rd marks Constitution day in Poland.
May 5th is Children's Day in Japan and Korea, Liberation day for Denmark and the Netherlands and Men's Day (yes, Men's Day) in Romania. It is doubtful that Cinco de Mayo will be observed in Arizona because some people object to proper immigration etiquette.
On May 6th, Saint Francis Xavier reached Goa, India.
On May 7th, Saint Joan of Arc pulled an arrow from her shoulder and ended the siege of Orleans.
May 8th marks not only Parents' Day in South Korea but V-E Day.