Queen Elizabeth II's birthday marked with huge celebration

Queen Elizabeth II celebrates 90th birthday 01:45

LONDON -- If there is one thing a party fit for a queen must be, it is grand. On Saturday, Britain showed up to celebrate the oldest and longest-reigning monarch in the U.K., Queen Elizabeth II.

Grand celebrations for Queen Elizabeth's 90th... 02:39

The queen emerged from Buckingham Palace dressed in a most vibrant shade of green. You could say at 90 years old, she knows a thing or two about commanding an audience.

Husband Prince Phillip, who just turned 95 on Friday, donned his traditional bearskin hat.

The fairy tale-esque festivities were led by Duchess Kate, Prince Harry and his stepmother Camilla. Prince William and Prince Charles followed the queen's carriage on horseback.

Trooping the Colour is equal parts birthday parade and military pageant. It's a centuries-old throwback, carrying or trooping the colors of regiments on the battlefield and allows the queen to meet her guards.

Guardsmen arrive back at Buckingham Palace from Horseguards Parade after the annual Trooping the Colour ceremony in central London, Britain June 11, 2016. REUTERS/Toby Melville

The queen is really showing no signs of slowing down. Last year, she made nearly 400 public appearances. This year, her schedule is expected to be just as crazy.

But at times during Saturday's two-hour celebration, the queen looked like she was ready to call it a day. It was only when she was surrounded by her family she looked most at ease.

Members of the royal family, including Prince Charles, Catherine, Duchess of Cambridge holding Princess Charlotte, Prince George, Prince William, Queen Elizabeth, and Prince Philip watch a flypast as they stand on the balcony of Buckingham Palace after the annual Trooping the Colour ceremony on Horseguards Parade in central London, Britain June 11, 2016. REUTERS/Toby Melville

Four generations gathered at Buckingham Palace to celebrate one woman.

But at 90, the queen looked more than happy to share the spotlight with Prince George and sister Charlotte, who made her balcony debut.