William, Kate, And Harry Visit Memorial Garden On The Eve Before Diana's Death Anniversary 

Prince William, Princess Kate  and Prince Harry made a poignant walk on Wednesday through the breathtaking all-white garden created in memory of Princess Diana.

On the rainy eve of the 20th anniversary of Diana’s death, the royal trio visited Kensington Palace to see the sunken garden that has been transformed to remember the beloved princess, who died in a Paris car crash on August 31, 1997.

At the garden, William, Kate and Harry were set to meet with representatives of the causes that Diana passionately supported — including Great Ormond Street Hospital, the National AIDS Trust, The Leprosy Mission, Royal Marsden Hospital, the English National Ballet and homeless charity Centrepoint — in order to highlight “the significant achievements of the Princess, and the legacy of her work which continues to resonate with so many today,” a spokesman said.

The floral display was conceived by Kensington Palace’s head gardener, Sean Harkin, whose team planted 12,000 bulbs last fall. He showed the royals the particular flowers — some of which were the princess’s favorites, including white lilies — that had been cultivated to mark her life.

White tulips, daffodils and hyacinths bloomed in spring and were followed by white roses, lilies, gladioli, cosmos, gaura and fragrant nemesia that arrived in summer. “As we’ve been working in the garden, many of our palace visitors have stopped to talk to us and share their own memories of Diana, Princess of Wales,” Harkin said in April. “We hope that our garden captures the energy and spirit that made her such a popular figure around the world.”

The palace is where the princes lived with their late mother and where they both have their London homes — William with Kate and their children, Prince George and Princess Charlotte, at Apartment 1a, and Harry at two-bedroom Nottingham Cottage within the complex.

As the summer has progressed, PEOPLE has been paying tribute to Diana (who appeared on the cover of the magazine a record 59 times) via the two-part television event

and in interviews with those who knew her best, including her younger brother Charles, 9th Earl Spencer, as well as those who worked with her to smash stigmas or alongside her at charities such as the Royal Marsden cancer hospital.

For full PEOPLE coverage of the 20th anniversary of Princess Diana’s death:

•Princess Diana: Behind the Headlines is streaming on the new People/Entertainment Weekly Network (PEN). Go to 

PEOPLE.com/PEN, or download the PEN app on your favorite mobile or connected TV device

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2 A New Royal Baby Is Here! Princess Sofia and Prince Carl Philip Welcome a ‘Very Cute Boy’

3 Princess Kate Channels Princess Diana in Near-Identical Floral Dress 36 Years Later

4 See Prince George’s New School Uniform, and Yes, It Includes Knee Socks!

5 Mourners Remember Princess Diana at Site of Fatal Crash: ‘She Has Never Gone Away and She Never Will’