When you're the head of one of the most powerful royal families in the world, you can do anything you please, including celebrating your birthday twice.
Queen Elizabeth II, who was born on April 12, 1926, celebrates her birthday two times a year, and as pompous as that may sound, there's a very good reason behind it.
For hundreds of years, it's been a tradition of the British royal family to celebrate the birthday of the reigning monarch on two separate occasions - the day they were actually born and a day for the public to enjoy.
The public celebration often includes artillery gun salutes (a 41-gun salute in Hyde Park, a 21-gun salute in Windsor Great Park, and a 62-gun salute at the Tower of London), and other celebratory activities, such as a military parade known as Trooping the Color. The entire family then gathers on the balcony of the Buckingham Palace where they watch a military fly-past.
The tradition is believed to have been started by King George II in 1748, but not many people know why.