Who: Queen Elizabeth II
What: Became longest-reigning UK monarch
When: 9 September 2015
Why: She passed the record set by Queen Victoria
Queen Elizabeth II became longest-reigning monarch of the United Kingdom.
She passed the record set by her great-great-grandmother Queen Victoria on 9 September 2015 who ruled for 63 years between 1837 and 1901.
Queen Elizabeth II assumed the throne on 6 February 1952 at the age of 25 upon the death of her father George VI.
At present, she is the head of the Commonwealth of Nations of 53 countries and the Supreme Governor of the Church of England.
In addition to the United Kingdom, the Queen is the sovereign of 15 Commonwealth realms including Canada, Australia and New Zealand. Incidentally, none of these 15 countries are in Europe.