Four days of celebrations honouring Queen Elizabeth II's 70 years on the throne are underway with a display of British military traditions stretching from the days of horse and cannon to the jet age.
Formal celebrations for the Platinum Jubilee begin with Trooping the Colour, an annual military review that has marked the sovereign's official birthday since 1760.
The Queen is expected to join the working members of her family on the balcony of Buckingham Palace at the end of the event when 70 aircraft are set to roar overhead.
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The jubilee is being commemorated with a four-day holiday weekend in the UK.
The celebration of Elizabeth's reign includes a service of thanksgiving Friday at St Paul's Cathedral in London, a concert at Buckingham Palace on Saturday and a pageant staged by thousands of performers drawn from schools and community groups around the country on Sunday afternoon.
Throughout the weekend, neighbourhood organisations and individuals are expected to hold thousands of street parties around the country, repeating a tradition that began with the Queen's coronation in 1953.
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Australia marks the Queen's milestone
There will be celebrations for the Queen right across the Commonwealth.
In Australia, the Sydney Harbour will bask in purple light at 9pm on Thursday during a "seven minutes for seven decades" celebration of the Queen's reign.
Other landmarks across the nation will also light up in royal purple over the next four days to celebrate the occasion.
Prime Minister Anthony Albanese will light a beacon in Canberra on Thursday night to honour the Queen.
"Today I have the great privilege of lighting a beacon as part of The Queen's Platinum Jubilee Beacons and to commence Platinum Jubilee celebrations in Australia," Albanese said in a statement.
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The government also plans to rename Aspen Island in Canberra after the Queen as a show of "appreciation and respect".
"I look forward to officially renaming Aspen Island to Queen Elizabeth II Island later this week as a mark of Australia's appreciation and respect for Her Majesty," Albanese added.
New Zealand has also marked the historic celebrations for the Queen's 70-year reign.
The Royal Regiment of New Zealand Artillery used four 25-pounder guns to react during their 21-gun salute at Point Jerningham.
In Wellington, similarly to Australia, a beacon will light up in royal purple at 9pm NZST.
It will be the second of 50 Commonwealth capital cities taking part in the Queeen's Platinum Jubilee Beacon event.