On Wednesday, Aug. 30, the eve of the 20th anniversary of Princess Diana’s death, Prince William and Prince Harry braved the London rain to pay tribute to their late mother, Diana, Princess of Wales at her memorial. The royal siblings, who were joined by William’s wife, Kate Middleton, made an emotional visit to “The White Garden” at Kensington Palace — a sunken garden transformed into a thoughtful tribute to the late Princess. The memorial features many of the royal’s favorite flowers — among them, 12,000 bulbs of white roses, gladioli, cosmos, gaura, fragrant nemesia, and white lilies.

Their Royal Highnesses toured the garden alongside Sean Harkin, who designed the tribute and Graham Dillamore, who knew the princess when he worked on the grounds some 30 years ago. “We know that Diana liked forget-me-nots,” Dillamore explained. “I always felt that she preferred the pastel, lighter color shades — the whites, the light pinks, the light blues — so I think what we’ve done here is very fitting.”

prince william at princess diana's memorial getty

(Photo Credit: Getty Images)

“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 told _People _ in April. “We hope that our garden captures the energy and spirit that made her such a popular figure around the world.”

Kate paid tribute to the mother-in-law she never knew with a poppy-printed dress by Prada — of course, poppies are a symbol of remembrance. She accented the floral ensemble with a neutral L.K. Bennett Fern stiletto.

In addition to taking in the breathtaking display, the golden royal trio met with representatives from many of the causes and charities supported by the People’s Princess, including the Royal Marsden and Great Ormond Street hospitals, the National Aids Trust, Centrepoint youth homelessness charity, and the Leprosy Mission. During the outing, Prince Harry explained, “All of us lost somebody,” before asking the charity workers who had worked with Diana to “tell me a story about my mom.”

A spokeswoman for Kensington Palace said, “The engagement will allow the princes to pay tribute to the life and work of their mother.” The palace is preparing for a deluge of new tributes as members of the public began days ago to leave flowers, cards, and candles at the iconic landmark’s gates.

The Telegraph reports the palace’s “robust” security staff have been briefed to point well-wishers in the direction of “The Golden Gates,” to the south of the palace, which will act as the focal point for those wishing to lay personal tributes. Of course, it’s the same spot in which a sea of flowers spontaneously formed after her death.

The princes surprised royals fans and onlookers as they read cards and messages ahead of the anniversary of her death, in scenes reminiscent from 20 years ago when Prince Charles and a young William and Harry took in the sea of tributes. A large banner is perhaps the most noticeable tribute to have popped up at the site. It shows pictures of the “Queen of Hearts,” as she lovingly became known, throughout her incredible life.

prince william and harry at princess diana's memorial getty

(Photo Credit: Getty Images)

Another tribute, a card attached to a bouquet of flowers, signed by royal fans Lynda and Victoria, acknowledges the efforts of Princes William and Harry in continuing their late mother’s incredible legacy. “You were a beautiful person inside and out and our country was so very lucky to have you as our Princess,” the note begins. “Thankfully your two boys are so like you in so many ways. You would be so very proud of the fine young men that they have become. You are still loved and missed as much today as you were 20 years ago.”

Prince William was just 15 and his brother, Prince Harry, only 12, when their beloved mother died from injuries sustained in a car crash in Paris on Aug. 31, 1997. She was just 36.

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This post was written by Candice Mehta-Culjak. It originally appeared on our sister site, Now to Love.