The birthday of Queen Margrethe II of Denmark is observed every April 16. Although it is not a public holiday, it remains an official flag-flying day in Denmark, honoring the former queen who reigned for 52 years before her abdication in January 2024. Queen Margrethe II was born on April 16, 1940, just after the German invasion of Denmark during World War II. Following her birth, a constitutional change allowed female succession to the throne, enabling her to ascend as queen at the age of 31. While she would traditionally make public appearances at either Amalienborg Palace or Marselisborg Palace on her birthday, she no longer does so after her abdication. Nonetheless, it is customary for Danes to raise the national flag in her honor on this day.