Queen Elizabeth II has passed another milestone as the U.K.'s longest-reigning monarch: Her Sapphire Jubilee - that's 65 years on the throne.
Having acceded to the throne at age 25, Elizabeth became the U.K.'s longest reigning monarch in September 2015 when she surpassed Queen Victoria's record of almost 64 years.
During her reign, the queen has been patron to hundreds of charities and organizations, as well as being one of the world's most well-traveled heads of state.
CNBC looks back at some of the British monarch's most memorable moments - before and after she took the throne.
Elizabeth was born April 21, 1926, the first child of the then-Duke and Duchess of York. In 1930, Elizabeth's parents gave birth to her sister, Princess Margaret Rose.
"Lilibet" leapt up the line of ascension faster than anyone had expected after her uncle, childless King Edward VIII, abdicated in December 1936 over his romance with divorced American socialite Wallis Simpson. Elizabeth's father became King George VI, putting her next in line to the throne.
During World War II, Elizabeth joined the Auxiliary Territorial Service at the age of 18 in 1945, with the rank of subaltern. By the time the war ended, she had become a junior commander.
Princess Elizabeth and Prince Philip, her third cousin and a member of the House of Schleswig-Holstein-Sonderburg-Gluecksburg, met in 1934 at the wedding of Philip's cousin, Princess Marina of Greece and Denmark. However it wasn't until July 1947 until the pair were officially engaged. They married on November 20, 1947.
A year later, November 14, 1948, Elizabeth gave birth to the first of her four children, Prince Charles. Before ascending to the throne, Elizabeth had two children, Charles and Princess Anne (1950), who were then followed by Prince Andrew in 1960 and Prince Edward in 1964.
King George VI died on February 6, 1952, making the 25-year-old princess Queen. More than a year later, on June 2, 1953, she was crowned at Westminster Abbey in the first British coronation to be televised.
Members of the royal family represent numerous organizations and charities worldwide. More than 3,000 groups list a royal as a patron or president. The Queen has been the patron of over 600 organizations which includes causes linked to the environment, education and health.
Being a member of the royal family means attending a whole range of gatherings from sport and charity events to gardening shows. However, as an avid race-goer and owner of several horses, Elizabeth especially looks forward to attending the Royal Ascot horse-racing event in Berkshire, a county west of London, every June.
Ceremony and pageantry are a core part of the British royal family. Among the regular duties Elizabeth carries out include opening parliament, making the annual Christmas speech and attending Trooping the Colour - a ceremony performed by regiments of the British and Commonwealth armies.
Elizabeth wasn't alone in undertaking national duties.
Elizabeth's travels have circled the world several times and she has met countless leading figures inside and out of Europe.
Elizabeth's relationship with the British public has always been a warm one.
In 2002, the U.K. celebrated 50 years of Elizabeth's reign. Celebrations were held across the country particularly during the summer, and the Queen and the Duke of Edinburgh traveled to every region of the U.K. and the Commonwealth to mark the occasion.
On November 20, 1992, the queen's 45th wedding anniversary, a fire at Windsor Castle caused extensive damage that took years to repair. But that was just one of a string of events that prompted the queen to declare 1992 her "annus horribilis." Prince Andrew's separation with the former Sarah Ferguson was announced in March. The next month, Princess Anne divorced Captain Mark Phillips. In June, Princess Diana's tell-all book was published. Its revelations included husband Charles' affair with Camilla Parker-Bowles.
Aside from horses, another animal the Queen is known for are her Pembroke Welsh corgis.
Being a royal, keeping up with appearances and official photographs are just some of the many duties the Queen has to undertake. This photo was taken in Buckingham Palace in December 2016.