A box of empty shells are prepared for a gun salute to commemorate the death of Britain's Prince Philip, Duke of Edinburgh, at the Parade Ground, Woolwich Barracks in central London on April 10, 2021. - Military guns will be fired across Britain and sporting events will fall silent on Saturday as part of worldwide tributes to mark the death of Queen Elizabeth II's husband, Prince Philip. (Photo by DANIEL LEAL-OLIVAS / POOL / AFP)