The Queen was born Princess Elizabeth of York on 21 April 1926, and was third in line to the throne, after Edward, Prince of Wales (King Edward VIII), and The Duke of York, her father.
When King George V, the Queen's grandfather, died in 1936, Edward VIII became King. However, within a year the King abdicated to marry Wallis Simpson. This meant that the Queen's father, King George VI, became King, thus putting the now-Queen first in line to the throne.
On 20 November 1947, the Queen married Prince Philip. The couple had met in 1934 at the wedding of Philip's cousin, Princess Marina of Greece, to the Queen's uncle, The Duke of Kent. Philip was the Prince of Greece but, to marry the Queen, he had to first become a British citizen which meant relinquishing his title. After he had given up his title, the British government discovered that, in fact, he needn't have done so.
During Queen Victoria's reign, a law was passed stating that any direct descendant of Queen Victoria would automatically have British citizenship, no matter their country of birth or residence. Prince Philip was a direct descendant of Queen Victoria and therefore a British citizen from birth.
In 1952, while the then-princess was on holiday with Prince Phillip in Kenya, they learned of her father's death. Queen Elizabeth has reigned since then.
She is currently the second longest serving monarch, after Queen Victoria. In her capacity as Queen, she's made more than 256 official overseas visits to 129 countries. She is the 40th monarch since William the Conqueror and is the only British monarch in history to have been properly trained in how to change a spark plug.
Since the aftermath of WWII to the creation of the Internet and mobile phone, the Queen has seen tremendous changes during her time on the throne. In her personal life, she, following the Queen Mother's example, has played a pivotal role as the strong matriarch of her family, having to deal with private matters which have become very public.
Here's one person's video tribute to the Queen. Have you or a family member ever met the Queen? Share your royal experiences below.