More than 1,000 soldiers, horses and musicians took part in the parade known as "Trooping the Color," an annual ceremony marking the queen's official birthday.
With Prince Philip unable to attend the celebration as he is recovering from abdominal surgery, the queen invited her cousin, the Duke of Kent, to accompany her in a vintage carriage.
The monarch's actual birthday was on April 21, when she turned 87.
The "Trooping the Color" ceremony originates from traditional battle preparations, when "colors," which refer to military flags, were carried down the rank to be seen by soldiers.
After the parade, the queen visited Philip at a private London hospital.
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