Trooping the Colour is a spectacular and colourful military parade that marks the official birthday of Queen Elizabeth II (whose real birthday is on 21 April). It takes place each second or third Saturday in June (to enjoy better weather), and millions of people around the globe can enjoy the event by watching the parade live on television. The first king to be honoured in that way was King George III (born on 4 June 1738). The celebration is now also known as The Queen’s Birthday Parade.
This year’s ceremony will take place on Saturday 17th June 2017.

More about Trooping the Colour on these websites :
– The British Military Ceremonial website
– The official website of the British Monarchy

More about Queen Elizabeth on these websites :
– The official website of the British Monarchy
– The BBC
– Project Britain