Earliest date on whichJeûne genevoiscan fall, while September 11 is the latest; celebrated on Thursday after the first Sunday of September. (Canton of Geneva)

Jeûne Genevois is a regional public holiday in Geneva marked by a day of remembrance and community gatherings on the Thursday after the first Sunday of September.
Dating back to the 16th century, Jeûne Genevois commemorates Geneva's historic deliverance from plagues and sieges. It is observed on the Thursday following the first Sunday in September, with the earliest possible date being September 5. Families and friends gather for shared meals, often featuring plum tart and roasted meats, after a morning of reflection. Churches hold special services to give thanks and pray for protection. Streets remain quiet as shops close, allowing residents to honor local heritage and unity. The day fosters a sense of community identity and gratitude among Genevans.
Jeûne genevois Canton of Geneva

The flag-flying day for Denmark's deployed personnel(Denmark)

Denmark’s Flag Day on September 5 honors Danish military personnel deployed abroad through nationwide flag displays.
Established in 2009, Danmarks Flagdag commemorates the service and sacrifices of Danish soldiers on international missions. Every year on September 5, Danes are encouraged to hoist the national flag at homes, public buildings, and military installations. Ceremonies and wreath-laying events are held at military cemeteries and memorials to pay tribute to fallen and serving personnel. The day fosters national unity and remembrance of Denmark’s contributions to peacekeeping and security operations. Although not a public holiday, it holds a special place in Danish society, reinforcing respect for the armed forces. Flag Day activities often include speeches by government officials and personal stories from veterans and their families.
The flag-flying day for Denmark's deployed personnel Denmark