Lady Diana Spencer was just 20 years old when she married Great Britain’s heir to the crown, Prince Charles. To the estimated 750 million viewers who watched the July 29, 1981 event on television, the wedding looked like something out of a fairy tale: a dashing prince waiting at the altar for the shyly smiling bride who emerged from a horse-drawn carriage wearing an impossibly gorgeous ivory taffeta wedding dress.

Diana’s popularity was so prevalent that coverage of the royal family became invasive. So it wasn’t long before it became public knowledge that “the marriage of the century” was no match made in heaven. Reports of discord and infidelities on both sides became constant tabloid fodder.

Despite the birth of their sons — Prince William on June 21, 1982, and Prince Harry on September 15, 1984 — no one was surprised when Prime Minister John Major announced on December 9, 1992, that Charles and Diana had separated.

Finally, on July 15, 1996, in a three-minute proceeding at Court Number One of Somerset House, the marriage of H.R.H. the Prince of Wales and H.R.H. the Princess of Wales (neither of whom was present) was dissolved. Diana received shared custody of Princes William and Harry. She retained the title Princess of Wales and continued her humanitarian work.

A little more than a year after the divorce was finalized, Diana was killed. She died from injuries sustained when the car she was riding in with her companion Dodi Fayed crashed in a Paris tunnel on Aug. 31, 1997. She was only 36.

Almost immediately following word of her death, makeshift memorials at her residence at Kensington Palace popped up and became a gathering place for public mourning and for people to bring flowers. Over in France, hundreds of Parisians and tourists marked her passing with a lower-key tribute by laying flowers near the scene of her death on the Place d'Alma. On Saturday, September 6, 1997, an estimated 2.5 billion people around the world tuned in to television and radio broadcasts of Diana’s funeral.

People felt they knew Diana and mourned her as a loved friend.

That quality gave her the ability to literally change the mindset of millions upon millions of people. While scores of books and documentaries have been coming out to commemorate the 20th anniversary of her death, here’s a look at how her life’s work—and even her death — have shaped the world.

She modernized the Idea of what a princess should be

Diana had a tremendous impact on modernizing the royal family, making it more accessible and changing people’s opinions about what the royal family meant to them. Not only she did say what was on her mind, she took on causes that the royal family would not normally take on, such as homelessness in the late 1980s. Diana would talk with people who were living in tents or under bridges while cameras followed her, saying, “If I’m going to have cameras pointed at me the whole time, I might as well use all this publicity for good.”

READ MORE: Was Princess Diana a Commoner Before Marrying Prince Charles?

Diana took a hands-on approach to humanitarian work

She was never afraid to shake hands with anyone, homeless or not, which her visit to officially open the UK's first purpose-built HIV/Aids unit at the London Middlesex Hospital proved. Without wearing gloves, Princess Diana shook the hand of a man suffering from the illness, publicly challenging the notion that HIV/Aids was passed from person to person by touch. In the ABC special, The Story of Diana, her brother Charles said, "She was not really a gloves person. She was very real about human contact. And what really mattered that day was to get across a very clear message that, 'I'm going to touch this gentleman … and we must help.”

She kept up this hand-on approach after her divorce by whittling her charity commitments down to six she cared most about. She wanted to avoid situations where she was just a letterhead, telling the chairman of the Washington Post Company, the late Katharine “Kay” Graham: “If I’m going to talk on behalf of any cause, I want to go and see the problem for myself and learn about it.”

READ MORE: Why Princess Diana Risked Her Life for Humanitarian Causes in Africa

She turned the spotlight on the paparazzi

In his eulogy for Diana, her younger brother, Charles Spencer, pointed out, “…that of all the ironies about Diana, perhaps the greatest was this — a girl given the name of the ancient goddess of hunting was, in the end, the most hunted person of the modern age.” Most people believed the press was to blame for the beloved princess’ death and a 2007 jury inquest definitively decided that Diana and Dodi had been unlawfully killed by a combination of their chauffeur Henri Paul’s erratic drunk driving of their Mercedes and the driving of the posse of paparazzi photographers who dogged their final journey. No formal charges were ever brought, but the Press Complaints Commission, a self-regulatory body in the U.K. that offers a code of conduct for those who cover celebrities, added this clause in an attempt to prevent another such tragedy:

"i) Journalists must not engage in intimidation, harassment, or persistent pursuit. ii) They must not persist in questioning, telephoning, pursuing, or photographing individuals once asked to desist; nor remain on their property when asked to leave and must not follow them. If requested, they must identify themselves and whom they represent."

READ MORE: The Final Years of Princess Diana

She put substance over style

Diana was well known for her fabulous fashion choices but once her divorce was final, she was intent on cleaning out her closets. In the HBO documentary, Diana, Our Mother, William remembers giving Diana the idea to give away her old clothes, which led to an auction for charity at Christie’s in New York City in June of 1997. The dresses ranged from Diana's girlish early period to her later sleeker and sexier looks. The proceeds from the auction benefited the Royal Marsden Hospital Cancer Fund and the AIDS Crisis Trust. Today, fabulous red-carpet frocks worn by stars at various awards shows (the Emmy’s, the Oscars, the Golden Globes and the Tony’s) are routinely auctioned off for worthy causes.

She inspired her sons to keep her legacy — and her laughter — alive

By their accounts in the documentary, Diana, Our Mother, her guidance in their formative years has helped Prince William and Prince Harry balance their public and private lives and allowed them to connect with people in an uncomplicated way. “She was very informal and really enjoyed the laughter and the fun,” William says. “But she understood there was a life going on outside the palace walls and she wanted us to understand that from a very young age.”

Harry remembers her telling him, “You can be as naughty as you want, just don’t get caught. She made the decision that both of us were going to have as normal of a life as possible. If that meant sneaking us out for a burger or to the cinema or driving out on country roads in her old BMW with the top down and Enya playing, then so be it.”

READ MORE: How Princes William and Harry Are Carrying out Princess Diana's Legacy

Both brothers have taken up numerous charitable causes and they use The Royal Foundation as the main vehicle to pursue their philanthropic activities. The brothers recently did a video for the Heads Together campaign, aiming to change the conversation around mental health in which they admitted they had not talked enough about how their mother’s death affected them when they were younger.

Right before she died, Diana took on the issue of landmines. She went to Bosnia where the landmines were and to war-torn countries in Africa. Just months before her death in 1997, Diana walked through an Angola minefield that was being cleared to call for an international ban on the devices. Three months after her visit, the Anti-Personnel Mine Ban Treaty was signed in Ottawa by 122 countries. To keep her promise to those affected, Harry, who is royal patron of the Halo Trust, an anti-landmine charity, recently called on world leaders to rid the world of land mines by 2025.

For the 20th anniversary of her death, Prince William and Prince Harry have commissioned a statue of Princess Diana that will be erected by the end of 2017. In the statement, both brothers said, “The time is right to recognize her positive impact in the U.K. and around the world with a permanent statue. Our mother touched so many lives. We hope the statue will help all those who visit Kensington Palace to reflect on her life and her legacy.”

Princess Diana trying on a kimono that she received as a gift at Nijo Castle, Kyoto, during an official visit to Japan on May 1986