LOOK BOOKHappy 31st Birthday Your Highness: Prince William Through the yearsPrince William Through The Years06.21.12LOOK BOOKHappy 31st Birthday Your Highness: Prince William Through the yearsPrince William Through The YearsSee photos of Prince William through the years.06.21.12 8:45 AM ETJohnny Eggitt / Getty ImagesHappy Birthday, William!He's 31 today! And what a life it's been. From his first day at nursery school, to his international exploits, to his iconic marriage to Kate Middleton, see photos of Prince William's finest moments. Tim Graham / Getty ImagesA Prince Is BornPrincess Diana holding her baby son, Prince William, at Kensington Palace. Tim Graham / Getty Images Prince Charles laughing with his sons as he lifts Harry onto William's shoulders in Kensington Palace. David Levenson / Getty Images Will on his first day at nursery school in September 1985. He arrived with Charles and Diana for his first day at Mrs. Mynor's Nursery School in Notting Hill, London. Tim Graham / Getty Images Philip, Charles, Diana and William (who is holding his hand over his eyes) as they stand on the balcony of Buckingham Palace for the Trooping the Colour ceremony in London in June 1988. Princess Diana Archive / Getty Images The Princess of Wales with her sons William and Harry on the chair lift during a skiing holiday in Lech, Austria, April 1991. Anwar Hussein / Getty Images Prince William enjoys playing with the hound dogs at Badminton Horse Trials in May 1991 in Badminton, England. Johnny Eggitt / Getty Images The royal family watches the parade march past as part of the commemorations of Victory over Japan Day. The commemoration was held outside Buckingham Palace and was attended by 15,000 veterans and tens of thousands of spectators. Princess Diana Archive / Getty Images Diana greets her sons on the deck of the yacht Britannia in Toronto, when they joined their parents on an official visit to Canada in October 1991. The Princess is wearing a Moschino suit. Tim Graham / Getty Images Prince William At Eton, the independent school for boys. Jeff J. Mitchell / Getty Images The Duke of Edinburgh, William, Earl Spencer, Harry and Charles walk outside Westminster Abbey during the funeral service for Diana, Princess of Wales. Hundreds of thousands of mourners lined the streets of Central London to watch the funeral procession. The Princess died in a car crash in Paris. Toby Melville, Newsmakers / Getty Images Prince William jokes with Marcela Hernandez-Rios, age 10, while teaching an English lesson to a classroom of Chilean schoolchildren during his Raleigh International expedition in December 2000 in the village of Tortel, Chile. Anthony Harvey / Getty Images Britain's Prince William takes part in an exhibition Polo match in July 2001 at Cirencester Park Polo Club in Gloucestershire. Alan Davidson, WireImage / Getty Images Harry and Will at the celebrations for Queen Elizabeth II's Golden Jubilee. David Cheskin, AFP / Getty Images Prince William plays with a rugby ball on the beach at St. Andrews in May 2003. At the time, the prince was two years into a four year History of Art degree at the Scottish university city. MJ Kim / Getty Images Prince William attends the wedding of Ed Van Cutsem and Lady Tamara Grosvenor at Chester Cathedral in November 2004. David Cheskin, AFP / Getty Images Prince William pauses in St. Salvator’s Quad at St. Andrews University. At the time, the prince was in the last year of his four-year course at the Scottish university. Tim Graham Picture Library / Getty Images Prince William takes part in an army training exercise, Winter Victory, at Paramali Village in Cyprus on in November 2006. Adrian Dennis, AFP / Getty Images Britain's Prince William breaks into a smile as he is inspected by his grandmother, Queen Elizabeth II, during the Sovereign's Parade at The Royal Military Academy in Camberley in December 2006. Richard Heathcote / Getty Images Harry, Will and Kate cheer on the English team during the RBS Six Nations Championship match between England and Italy in February 2007.