Military personnel have been at the heart of celebrations for the first day of Her Majesty The Queen's Platinum Jubilee.
The Queen's Birthday Parade began with Trooping the Colour, inspected by His Royal Highness the Prince of Wales.
1st Battalion Irish Guards trooped their colour, or flag.
The colour was used in past times as a rallying point during battle and an important symbol of recognition.
Watch: Military gun salutes take place across the nation.
The Household Division have been Trooping the Colour since at least 1755 and it has become a valued icon of British military and Royal life.
Following Trooping the Colour, the King's Troop Royal Horse Artillery made their way to Hyde Park for the next military display.
They fired 21 rounds in a gun salute for the Queen's Birthday, 21 rounds for Coronation Day and an extra 20 rounds added to each because the firing took place in a Royal Park.
The Honourable Artillery Company fired 124 rounds at the Tower of London.
4th Regiment Royal Artillery fired 42 guns in salute in York Museum gardens, whilst 105th Regiment Royal Artillery did so from the impressive Stirling Castle.
Watch: 'An absolute honour': 16 Regiment Royal Artillery gunners on firing Platinum Jubilee gun salute.
Flight Lieutenant Gordon Halton, 16 Regiment Royal Artillery, told Forces News: "We actually only found out we were going to be doing this approximately a week ago, so we crammed in a lot of training in the short space of time we did have.
"At the start of the week there was a lot of nerves, anticipation, would we be ready in time. Thankfully, as you hopefully saw today, it was slick, professional.
"There was no need for anyone to have any nerves or have any doubt about what we could achieve on the day."
More than 70 aircraft from the Royal Navy, British Army and Royal Air Force took part in a six-minute flypast to mark the end of the Queen's Birthday Parade.
The Queen stood on the balcony of Buckingham Palace to watch the aircraft fly over alongside other members of the Royal Family.
Thousands lined The Mall as aircraft including Typhoon fighter jets, British Army Apache helicopters and Red Arrows flew over.
Earlier, the Queen made her first balcony appearance of her Platinum Jubilee celebrations – to take a salute of her soldiers returning from Trooping the Colour.