Soldiers in scarlet tunics and bearskin hats marched to celebrate the birthday of Queen Elizabeth II.
The queen actually turned 81 on April 21. But one of the many perks of wearing the crown is a second, official birthday in June, marked with the annual Trooping the Color parade.
The British monarch wore a bright green coat and hat to inspect the troops gathered in her honor in central London. Dignitaries, including former Prime Minister Margaret Thatcher, outgoing Prime Minister Tony Blair and Foreign Secretary Margaret Beckett, also attended the annual event.
The parade is a full-on display of British pageantry, with more than 1,100 soldiers marching down the Mall the wide, leafy boulevard that runs from Buckingham Palace toward Trafalgar Square in full regalia.
The queen herself used to ride in the parade, but since 1986, the year her horse retired, she has chosen to ride in a carriage with her husband Prince Philip.
Each year, a regiment is chosen to present its color, or flag, to the monarch. This year, the regiment was the Number 7 Company Coldstream Guards.
The queen took the salute and inspected the troops on Horse Guards Parade, and then the royal family returned to Buckingham Palace, gathering on the building's famous balcony for a flypast of military aircraft.
The queen was joined on the balcony by many family members, including Prince William who was in military uniform and Princesses Eugenie and Beatrice, the daughters of Prince Andrew and Sarah Ferguson, the Duchess of York.
Camilla, Duchess of Cornwall, stood between her stepson Prince William and her husband, Prince Charles. Prince Harry did not attend the annual event, as he is training with his army unit.
The event which began as traditional military preparations is now a huge draw for tourists, with thousands lining the parade route to catch a glimpse of Britain's royals.
Nine people were arrested during the parade in what police said was an operation aimed at preventing a breach of the peace. Police said they were responding to reports that fathers' rights group Fathers 4 Justice was planning "a spectacular event."
The group's members have a history of high-profile stunts, including invading a television studio during a live broadcast and climbing prominent structures clad in superhero costumes.
The seven men and two women were released without charge after the ceremonies finished.
Last year, police stopped two activists dressed only in Union Jack boxer shorts from blocking the queen's carriage during the ceremony.