Though Queen Elizabeth II was born in London on April 21, 1926, her birthday is officially celebrated on June 9.
Since 1748 during the reign of King George II, the United Kingdom has celebrated the reigning monarch's birthday on a set day in the summer to guarantee pleasant weather for an extravagant celebration.
While different countries throughout the Commonwealth mark the occasion on different days, Queen Elizabeth II's birthday is annually celebrated on the second Saturday of June. That day, London hosts the Queen's Birthday Parade, also known as Trooping the Colour. This military pageant is comprised of a parade of 1,400 officers with 200 horses, performances by more than 400 musicians, and a fly-past by the Royal Air Force.
A handful of celebrities have the unfortunate luck of sharing a birthday with a woman throwing one of the largest parties in the world. Queen Elizabeth's birthday also overlaps with that of past famous world leaders.