Today marks the 19th anniversary of the death of one of the world’s most enigmatic figures, Diana, Princess of Wales: a woman her brother Charles referred to as “the unique, the complex, the extraordinary and irreplaceable Diana.” 

A Blue Mood - Diana In 1995 At the Help the Aged Golden Awards, Nov. 1995, Diana wore a suit in powder blue with gold buttons. Photo: JOHNNY EGGITT/AFP/Getty Images

On Aug. 31, 1997,  Diana died of injuries sustained in a car crash in the  Pont de l'Alma road tunnel in Paris. Her companion, Dodi Fayed, and the driver of the Mercedes-Benz S280, Henri Paul, were pronounced dead at the scene; the bodyguard of Diana and Dodi, Trevor Rees-Jones, was the only survivor.

Diana's funeral Diana's funeral was held September 6, 1997 Photo: Reuters

An 18-month French judicial investigation found that the crash was caused by Paul, who lost control of the car at high speed while intoxicated. 

Whole nations of people found it hard to deal with the banality of the accident that ended her life and as a result, several conspiracy theories surrounding her death emerged. Dodi's father,  Mohamed Al-Fayed, promoted many of them.

Here are four you might have heard and one you probably haven't. 

Diana Was Killed By MI6

Richard Tomlinson, a former MI6 officer, claimed in a sworn statement to the French inquiry in May 1999 that Britain's MI6 had been involved in the crash. The previous August, he had been reported by the BBC to have claimed that Paul was working for the security services and that one of Diana's bodyguards, either Trevor Rees-Jones (now known as Trevor Rees) or Kes Wingfield, was a contact for British intelligence.

Tomlinson alleged that MI6 was monitoring Diana before her death, had told Al-Fayed that Henri Paul was an MI6 agent and that her death mirrored plans he saw in 1992 for the assassination of then President of Serbia Slobodan Milošević, using a strobe light to blind his chauffeur.

However, on 13 February 2008, Tomlinson told the inquest that he may have misremembered and that he had no evidence that Paul was an MI6 agent.

Diana Was Pregnant When She Died

One of the main motives which has been advanced for alleged murder includes suggestions Diana was pregnant with Dodi Fayed's child. The alleged dislike of the idea of a non-Christian within the British Royal Family meant such a relationship between the mother of the future king and a prominent Egyptian Muslim would not be tolerated.

In Mohamed Al-Fayed’s view, which he repeated in court at the inquest in February 2008, Prince Philip, Prince Charles and Diana's sister Lady Sarah McCorquodale were all involved in a plot to kill the princess and his son. Jeffrey Steinberg of the Executive Intelligence Review, a publication of the American Lyndon LaRouche movement, has also put forward theories that the Princess of Wales was murdered by the security services on instructions from Prince Philip.

In January 2004, the former coroner of The Queen's Household, Dr. John Burton, said (in an interview with The Times) that he attended a post-mortem examination of the princess's body at Fulham mortuary, where he personally examined her womb and found her not to be pregnant.

Dodi Bought An Engagement Ring And Was Going To Propose

On August 30, Dodi Fayed is said to have purchased an engagement ring from the jewelry store of Alberto Repossi.

Repossi said in 2003 that the ring had been placed on Diana's finger in a St. Tropez hotel, and was being resized for future collection in Paris.

Mohamed Al-Fayed made the assertion in television interviews that the couple were going to announce their engagement on the Monday after the accident, Sept. 1 1997.

CCTV evidence shown at the inquest indicates that Dodi left the store with nothing more than a catalogue.

Furthermore, since an announcement of such magnitude from the Princess of Wales would have been a substantial media event of worldwide interest, it would have required significant preparation. No evidence was found that any such preparation had been made.

A White Fiat Uno Caused The Mercedes To Swerve And Crash

Mohamed Al-Fayed alleged that a white Fiat Uno was being used by MI6 as a means of causing the Mercedes to swerve and crash into the side of the tunnel.

Al-Fayed further alleged that the Fiat Uno was owned by a French photojournalist named Jean-Paul James Andanson, a security services agent according to Fayed, who had photographed Diana while she was at his villa in St. Tropez in July 1997. Andanson's suicide in May 2000, Al-Fayed claimed, was either due to guilt over what he had done or because he was assassinated by the French or British security services to silence him.

In fact, Andanson had been interviewed by French police in February 1998, and had been able to provide documentary evidence about his movements on August 30/31 which had satisfied them that he could not have been the driver of the Fiat Uno involved. These demonstrated that Andanson could only have been at his home in Lignieres, 177 miles from Paris, at the time of the crash. Elizabeth, his widow, said at the London inquest in February 2008 that her husband had been at home with her at the time of the accident.

Diana Is Not Buried In her Official Resting Place

Officially, the princess is interred on a small island in the middle of a lake located on the Spencer family estate at Althorp. Her final resting place features a modest temple, along with another commemorative statue at the entrance of the grounds.

Diana's tomb Diana's official resting place at Althorp Photo: Reuters

Another version of the princess's burial, however, suggests that she was secretly cremated and her ashes interred in the family chapel at the church of St. Mary the Virgin with St. John in the nearby village of Great Brington. The Spencers have held Althorp for centuries, and 19 generations of Spencers, including Diana’s father, are buried inside the church, dating back to 1522. Locals contend the myth was created to prevent tourists swarming the tiny village and blocking traffic. 

Charles. Viscount Althorp Diana's brother Charles reviews floral tributes to Diana Photo: Reuters