Media playback is unsupported on your device Media caption Irish Guards mark the Queen's 91st birthday

Buckingham Palace tweeted a picture of the monarch as a baby on her christening day, where she is held by her mother Elizabeth, Duchess of York. LONDON (AP) — Britain marked Queen Elizabeth II's 91st birthday on Friday with gun salutes, as the monarch herself enjoyed a family day and a trip to the races. But this year, Britain’s longest-reigning monarch will mark her “official birthday” on June 17th with a parade in London known as the “Trooping the Colour” ceremony — a tradition from 1748, where the public can take part in honoring their King or Queen.
Queen Elizabeth II celebrates her 91st birthday.