(CNN) Who can forget the Queen's reaction at Royal Ascot in 2013 when her racehorse, Estimate, won the prestigious Gold Cup?
It was a rare moment when her public front slipped as the then 87-year-old -- with all the enthusiasm of a young girl -- watched on from the Royal Box and urged her mare to the winning line.
It was an extraordinary moment that will live long in the memory for many observers as it offered a human side rarely displayed among all the pomp and protocol.
The races were among the few occasions when the Queen could allow her guard to drop in public for a few moments and she could mix amongst the racegoers as a pure racing fan. However, as those in the sport know, she was far from just being a fan.
Horses were central to the Queen's life from a very young age.
She was just 16 when she first visited a racing stable. Her father, George VI, went with her to cast his eye on two prime race horses -- Big Game and Sun Chariot.
"She watched them do some gallops ahead of some big races that were imminent," journalist and author Julian Muscat told CNN in 2018.
"Afterward, she went and patted them on the head and loved the feel and the silkiness of their coats.
"The story goes that she didn't wash her hands for the rest of the day."
Her love for horses remained undiminished, whether it was her success breeding native ponies, her equine charitable work or, most notably, her long and successful relationship with the thoroughbred racehorse.
And while Estimate may have provided the Queen with arguably her finest win as an owner, she enjoyed widespread success with multiple winners to her name since her coronation in 1953.
She was named British Flat racing Champion Owner in 1954 and 1957 and -- with victories at the St Leger Stakes, Epsom Oaks, 1,000 Guineas and 2,000 Guineas -- the only one of the five British Classic Races that eluded her was the Epsom Derby.
Of all the horses she successfully owned, most of them were home-breds.
It's a side of the sport she took a particular interest in and it's said that she took satisfaction from having seen that horse as a foal, grow up and then go to the races.
She made regular visits to the Royal Stud in Sandringham, Norfolk and, once the horses finished racing, they remained in her care in retirement. Her first public appearance after the Covid-19 lockdown in 2020 was, of course, her riding one of her ponies around the grounds of Windsor Castle.
The racing world was quick to pay its respects following news of her death.
Top jockey Frankie Dettori said it was an "honor of a lifetime" to ride for the Queen on many occasions.
"As a man, it was a greater honor to have known such a remarkable person," he added in a statement on Twitter.
"I will be forever grateful for the time, kindness and humour Her Majesty warmly afforded me. Thank you, ma'am."
It is a common sight to see trainers and owners briefing jockeys before races, discussing tactics and opportunities, and the Queen was no different.
If she had a horse running in her colors at Royal Ascot, there is no doubt that she would have been down in the parade ring, talking to the trainer and jockey while studying the other runners in the race.
Her knowledge of racing was said to be encyclopedic and she was the unofficial figurehead of British racing.
Such was her importance to the sport, race meetings were canceled in the UK as soon as her death was announced.
Many of the overseas horses that come to Royal Ascot from the likes of the United States, Hong Kong and Australia don't come for the prize money, which is behind practically any other race, but they come for the prestige, much of which was associated with the Queen.
She missed the festival for the first time since her coronation this year as she continued to experience mobility issues.
"To sit with the Queen is a memory I'll never forget for the rest of my life," American trainer Wesley Ward told Royal Ascot in 2016.
"We had a wonderful talk about the horses and she was very interested in talking to me, in as far as my horses kind of shoot to the front and I've been lucky enough to win a couple that way. And she was asking me all about my tactics and how I train them to do that.
"So I just kind of looked at her and I said, 'Well, when you go to the front, they gotta catch you.' And she said, 'That's what I tell my trainers'... It was just like you're sitting talking to somebody who's at the races. You've gotta kind of pinch yourself and realize you're talking to the Queen of England."
Her interest in horse racing was passed down through the generations, and although it was never stronger than in the Queen's reign, hopes are high that Prince Charles and the Duchess of Cornwall, who have had Royal Ascot runners in recent years, will continue the royal tradition.