London ( CNN ) -- Sixty years ago Monday , a 25-year-old woman visiting a remote part of Kenya got a message that her father had died . She cut her trip short and flew home to London . Prime Minister Winston Churchill met her at the airport -- because with her father dead , she had become Queen Elizabeth II . Celebrations of her Diamond Jubilee , marking six decades on the throne , officially begin Monday and continue through June , when London will mark the anniversary of her coronation with festivities including up to 1,000 boats sailing up the River Thames . On Monday , the queen thanked the public `` for the wonderful support and encouragement that you have given to me and ( husband ) Prince Philip over these years . '' She said in the open letter that she planned to `` dedicate myself anew to your service . '' She called on people to `` give thanks for the great advances that have been made since 1952 and to look forward to the future with clear head and warm heart '' in a brief letter that she signed simply `` Elizabeth R. '' She was honored with a 41-gun salute in London 's Hyde Park Monday , and a 21-gun salute in Edinburgh , Scotland . Two new photographs of the queen were released Monday as part of the Diamond Jubilee celebrations , showing her wearing a necklace worn by Queen Victoria in her own Diamond Jubilee portrait in 1897 . She is the oldest British monarch in history , but has not yet passed her great-great-grandmother Victoria as the longest-reigning one . Elizabeth II was not in line to the throne when she was born April 21 , 1926 . But the fate of Lilibet , as she was known to her friends , changed when her uncle Edward abdicated the thone to marry Wallis Simpson , an American divorcee . That made Elizabeth 's stuttering father George king , and Elizabeth became queen when he died aged 56 following a lung operation . The queen seems to have inherited her mother 's longevity . Queen Elizabeth the Queen Mother , as she was known once George VI died , lived to be 101 . The British monarch has no political power but Elizabeth has immense power as a figurehead . She is officially the head of state of 16 countries that used to be part of the British Empire , has met presidents and prime ministers , and has seen the world change beyond recognition during her reign . Following the queen 's visit to Ireland in 2011 -- the first by a British monarch since Irish independence -- Prime Minister David Cameron described the effect Elizabeth is able to have when she chooses . At a state banquet , `` suddenly she started speaking in Irish , in Gaelic , '' Cameron recalled . `` It came as a complete surprise to everybody including the president ( of Ireland , ) who looked around the room and mouthed the word 'Wow . ' It was that kind of moment . You do n't often get people at state banquets saying 'Wow , ' but it was a wow moment . '' CNN Royal Correspondent Max Foster contributed to this report .
NEW : The queen is honored with a 41-gun salute in London . She thanks the public for their `` wonderful support and encouragement '' Celebrations of her Diamond Jubilee will continue through June . In an address to Parliament, Queen Elizabeth II said she was proud that Britain had been able to celebrate its 70th anniversary ``without any loss or damage being done to our national security or economy '' but