Princess Diana's brother, Charles Spencer, is paying tribute to his sister 28 years after her death. "Flowers we cut this morning from Althorp's gardens for the Island," Spencer, 61, wrote via Instagram on Sunday, August 31. "Always an impossible day." Alongside the message, Spencer shared a photo of a bouquet of pink and white flowers and another image of the private island where Diana is buried at Althorp Estate in West Northamptonshire, England. Charles has been custodian of the estate since 1992, after the death of his father, John Spencer.