Every year, towards the end of her annual Summer Holiday at Balmoral Castle, the Queen hosts the annual Ghillies Ball in the Ballroom of the Castle, like she did on this day in 1991. The Queen (wearing the Girls of Great Britain & Ireland Tiara) was joined by the Duke of Edinburgh, Queen Mother (in the Greville Tiara), Prince and Princess of Wales, Princess Anne, and the Duke of York. The event is always private, but was filmed that year for the documentary, Elizabeth R.