Charles Spencer is remembering his sister, Princess Diana.

In an Instagram post on Sunday, Aug. 31, Charles, 61, posted a photo of the flowers he brought to the burial site of the late princess of Wales at Althorp Estate as he marked the 28th anniversary of her death.

“Flowers we cut this morning from Althorp’s gardens for the Island,” he wrote in the caption, referring to Diana’s grave at his family’s estate in West Northamptonshire, England. “Always an impossible day,” Charles said.

The photo of the bouquet of white and pink roses in honor of Diana were shared alongside a snap of the private island where she is buried at Althorp Gardens.

Princess Diana was killed in a devastating car crash in Paris on Aug. 31, 1997, along with her partner Dodi Fayed and driver Henri Paul. The beloved royal left behind her two sons, Prince William, then 15, and Prince Harry, then 12, whom she shared with King Charles, formerly the Prince of Wales.

Princess Diana’s final resting place at Althorp Estate was decided by her brother Charles. She is buried on a secluded private island in Pleasure Gardens on the grounds, which are also known as Oval Lake Grave.