The White Garden, at Kensington Palace in London - the former home of the Princess who died in a vehicle crash in Paris - has been created to mark 20 years since she died on August 31, 1997 in a high-speed Paris auto crash.
Outside the palace, Britons left flowers of their own Tuesday.
The sea of flowers outside the gates of Kensington Palace where thousands of mourners from across Britain and the world payed their last respects to Diana, Princess of Wales in 1997.
However the White Garden is set to be one of the most iconic memorials yet, with tributes from the public already being left for Diana at the Kensington Palace gates ahead of the anniversary tomorrow.
Announcing the artwork in January this year, William and Harry had said, "It has been 20 years since our mother's death and the time is right to recognise her positive impact in the United Kingdom and around the world with a permanent statue".
The 36-year-old princess was with her boyfriend Dodi Fayed and her bodyguard Trevor Rees-Jones in a Mercedes pursued by paparazzi when the auto crashed in Paris' Alma Tunnel at more than 60 miles per hour (100 kph) on August 31, 1997.
Diana had died in August 1997 in Paris when William was 15 and his brother was 12. She had divorced her husband Charles, Prince of Wales, in 1996. "I remember crying my heart out on my honeymoon", she said, likening herself to a "sacrificial lamb".
According to Town and Country, Head Gardener Sean Harkin led the group on a walk around the grounds and pointed out all of Diana's favorite flowers, including forget-me-nots, white lilies, white roses, tulips, narcissi, and Cosmo daisies.
"She was such a fun, handsome person, and a humanitarian", Tasha says.
"I really did expect more people to be here, maybe more will come in the afternoon", she adds.
A smudged note, signed by the Gould family, from Egham in Surrey, reads: "Still not forgotten after 20 years", while another letter says that her "two boys are like you in so many ways".
"It's the heaviest cake I've ever carried", he said.
We look back at the day Britain stood still.