People observe a minute's silence for Britain's Prince Philip at Hillsborough Castle, Northern Ireland, Saturday, April 17, 2021. AP

Members of the military march ahead of the funeral service of Britain's Prince Philip, Duke of Edinburgh in Windsor Castle in Windsor, west of London, on April 17, 2021. AFP

- Britain's Prince William, Duke of Cambridge (L) and Britain's Prince Harry, Duke of Sussex follow the coffin during the ceremonial funeral procession of Britain's Prince Philip, Duke of Edinburgh to St George's Chapel in Windsor Castle in Windsor, west of London, on April 17, 2021. AFP

Britain's Prince Charles, from front left, Princess Anne, Prince Andrew. Prince Edward, Prince William, Peter Phillips, Prince Harry, Earl of Snowdon, and Tim Laurence follow the coffin as it makes it's way past the Round Tower during the funeral of Britain's Prince Philip inside Windsor Castle in Windsor, England Saturday April 17, 2021. AP

A view of the gun salute at The Tower of London before the funeral service of Britain's Prince Philip, in London, Britain April 17, 2021. Reuters

Members of the Royal family follow the coffin during the ceremonial funeral procession of Britain's Prince Philip, Duke of Edinburgh to St George's Chapel in Windsor Castle in Windsor, west of London, on April 17, 2021. AFP

Queen Elizabeth II arrives at St George's Chapel for Britain Prince Philip's funeral at Windsor Castle, Windsor, England, Saturday April 17, 2021. Reuters

Britain's Queen Elizabeth II, obscured left, looks on the flag draped coffin in St. George’s Chapel during the funeral of Prince Philip, the man who had been by her side for 73 years, at Windsor Castle, Windsor, England, Saturday April 17, 2021. AP

People observe a minute's silence outside Windsor Castle during the funeral of Britain's Prince Philip in Windsor, England, Saturday, April 17, 2021. AP

Pall Bearers carry the coffin of Britain's Prince Philip, husband of Queen Elizabeth, into St George's Chapel, Windsor Castle in Windsor, Britain, April 17, 2021. Reuters

Pallbearers carry the coffin of the Duke of Edinburgh during his funeral, at St George's Chapel in Windsor Castle, Windsor, England, Saturday April 17, 2021. AP

Britain's Queen Elizabeth II (L) and Britain's Prince Andrew, Duke of York attend the funeral service of Britain's Prince Philip, Duke of Edinburgh inside St George's Chapel in Windsor Castle in Windsor, west of London, on April 17, 2021. AFP

The coffin of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, is taken into St. George's Chapel for a funeral service, in Windsor, Britain, April 17, 2021. Reuters

A screen in Piccadilly Circus displays images of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in London, Britain, April 17, 2021. REUTERS

People applaud after observing a silence outside Windsor Castle during the funeral of Britain's Prince Philip in Windsor, England, Saturday, April 17, 2021.REUTERS

A general view shows the coffin of Britain's Prince Philip, Duke of Edinburgh laid onto a modified Land Rover Defender in the quadrangle ahead of the ceremonial funeral procession to St George's Chapel in Windsor Castle in Windsor, west of London, on April 17, 2021. AFP

A screen in Piccadilly Circus displays images of Britain's Prince Philip, husband of Queen Elizabeth, who died at the age of 99, in London, Britain, April 17, 2021. Reuters

Pallbearers carry the coffin into St George's Chapel during the funeral of Britain's Prince Philip, Duke of Edinburgh in Windsor Castle in Windsor, west of London, on April 17, 2021. AFP

From left, Viscount Severn, Sophie Countess of Wessex and Lady Louise Mountbatten-Windsor during the funeral of Prince Philip, at St George's Chapel in Windsor Castle, Windsor, England, Saturday April 17, 2021. AP