London, England (CNN) -- British troops dressed in red jackets and black bearskin hats put on a military spectacle in London on Saturday to mark Queen Elizabeth's official birthday.
They marched to music as other troops sat on horses for the annual ceremony, known as Trooping the Color. It took place on the Horse Guards Parade, the marching ground within sight of the queen's residence at Buckingham Palace.
Queen Elizabeth, wearing a lilac outfit and hat decorated with bow of pink and green, sat front and center to watch what many consider the most celebrated event on the British royal calendar.
The queen, who turned 84 this year, was born on April 21 but celebrates her birthday on a Saturday in June when the weather is better.
Trooping the Color dates at least to the early 18th century, when the colors -- or flags -- of the battalion were "trooped" down the ranks so they could be seen and recognized by all the soldiers, according to Buckingham Palace and the British Army.
Since 1748, the ceremony has also marked the sovereign's official birthday, the palace said.
Queen Elizabeth has attended it every year except for 1955, when a national rail strike canceled the event, the palace said.
A limited number of tickets are available to the public to watch the event at the Horse Guards Parade. It is also shown live on TV, and others can watch the troops go by on The Mall, which leads from the palace to the parade.
The ceremony is carried out by fully operational troops from the Household Division of the British Army.
Only one color can be trooped at a time, and the five Household Regiments -- Grenadier, Coldstream, Scots, Irish, and Welsh Guards -- take their turn each year. This year it was the turn of the 1st Battalion Grenadier Guards, who recently returned from Afghanistan.
At the end of the ceremony, the queen climbed into an open-top horse-drawn carriage for the ride back to Buckingham Palace. The crowds along The Mall, lined with Union Jacks, cheered as she went past.
The queen then stood on the palace balcony to watch a military fly-past that ended with aircraft trailing red, white, and blue, the colors of the British flag. She waved to the crowds and was joined by other members of the royal family, including her husband, Prince Philip; her son, Prince Charles; and her grandson, Prince William.
CNN's Melissa Gray contributed to this report.