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Lord Louis Mountbatten - Lord Louis Mountbatten was Prince Philip's uncle and was very close to King Charles, who considers him a mentor. The British Royal Navy officer—born Prince Louis of Battenberg—was the victim of a terrorist attack while holidaying at his vacation home.

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Lord Louis Mountbatten - A member of the Irish Republican Army (IRA) had attached a bomb to his wooden boat, which exploded when Mountbatten set off to go fishing with one of his grandsons, Nicholas Knatchbull. The boat was destroyed and Mountbatten, who was pulled out alive by a fisherman, died from his injuries shortly after.

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Prince Gustaf Adolf of Sweden -

Prince Gustaf Adolf, father of the current Swedish King Carl Gustaf, died in a tragic plane crash while traveling back from the Netherlands to Stockholm on January 26, 1947. The flight had made a routine stop in Copenhagen, but as soon as it took off, at an altitude of only 50 m (164 ft), it dove head-first to the ground and exploded. All 22 people that were on board died. 

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Grace Kelly - Grace Kelly, who was previously a Hollywood actress, retired at 26 to become the princess of Monaco by marrying Prince Rainier III. However, the fantasy came to a brutal end on September 14, 1982.

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Grace Kelly - After spending some time in their family's home in Roc Agel, she and her daughter Stéphanie left for the palace in Monaco on September 13, 1982. On their way back, Kelly had a minor stroke while driving and lost control of the car. Both women were taken to the hospital in critical condition, but the icon succumbed to her injuries and died a day later, on September 14, 1982.

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Princess Diana - The passing away of The People's Princess is surely one of the best known contemporary royal deaths. On August 31, 1997, Lady Di got involved in a dreadful car crash after she left the Ritz Hotel in Paris.

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Princess Diana - Her driver, Henri Paul, and then boyfriend, Dodi Fayed, both died at the scene of the accident, while Diana died from her injuries in the hospital a few hours following the accident. The only survivor was her bodyguard, Trevor Rees-Jones.

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Nepalese royal massacre - On June 1, 2001, the Nepalese royal family was hit by a terrible tragedy. 29-year-old Prince Dipendra (left) opened fire on his family and killed his father (King Birendra), his mother, his younger brother, and other members of the family before shooting himself in the head.

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Nepalese royal massacre - Allegedly, Prince Dipendra was furious that his mother objected to his choice of bride. However, since he didn't immediately die after shooting himself, he was proclaimed king while being in a coma.

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Nepalese royal massacre - After a three-day "reign," he passed away on June 4, 2001. A new king, King Gyanendra, was crowned and reigned until 2008. He was the last King of Nepal.

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Stefano Casiraghi - Stefano Casiraghi was an Italian sportsman, businessman, and second husband of Princess Caroline of Monaco. He tragically died in a racing accident on October 3, 1990 at age 30. It was supposed to be his last race, as he had decided to retire after the competition.

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Mark Shand - Mark Shand may not be a royal himself, but he's the younger brother of Camilla.

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Mark Shand - Shand died after a celebration for his charity in New York. After the writer left a bar, he reportedly lost his balance, fell, and hit his head. It was revealed by an investigation that Shand's skull was just 1 mm thick, and this eventually led to his death after spending nine hours in coma.

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Astrid of Sweden, Queen of Belgium -

Princess of Sweden by birth and first wife to King Leopold III of Belgium, she was mother to former Belgian King Baudouin and King Albert II, as well as Princess Joséphine-Charlotte, who would later become Grand Duchess consort of Luxembourg.

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Astrid of Sweden, Queen of Belgium -

The couple went on holiday to Switzerland in August 1935. On August 29, they decided to go for a hike in the mountains before going back home. The King took the wheel with Astrid sitting in the passenger seat next to him, while their driver took a seat in the back. As Astrid pointed out something to her husband, he got distracted, lost control of the convertible car, and violently slammed into a pear tree. Ejected by the shock, the Queen fractured her skull and died almost instantly. She was only 29 years old.

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Prince Friso of the Netherlands - Prince Friso, the second son of Queen Beatrix, tragically passed away on August 12, 2013, after a year and a half in coma.

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Prince Friso of the Netherlands - While spending time with his family at an Austrian ski resort in 2012, the prince got buried by an avalanche. He spent 18 months in coma, and eventually died of complications.

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Anne Boleyn -

Anne Boleyn was the second wife of King Henry VIII, who married her in 1533. The queen soon gave birth to a daughter, followed by three miscarriages. The fact that she couldn't produce a male heir led Henry to accuse her of adultery, and conspiracy—not witchcraft as some rumors say— in order to annul the marriage and marry his then-mistress and Anne's maid of honor, Jane Seymour. The Queen was tried and found guilty on May 19, 1536 and was beheaded four days later by a French swordsman.

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King Albert I of Belgium -

On February 17, 1934, King Albert I of Belgium went for a climb—which was one of his passions— in Marche-les-Dames, near the province of Namur in Belgium. But several hours after his departure, he still wasn't back. 

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King Albert I of Belgium -

A search party was soon organized, only to find the King's body. Evidence confirmed that he died following a fatal fall from a cliff. He was succeeded by his son, King Leopold III.

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Prince George, Duke of Kent -

The fourth son of King George V died on August 25, 1942, at age 39 during World War II. On that day, he boarded a military plane to Iceland, which later mysteriously crashed in Scotland.

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Princess Marina, Duchess of Kent -

The widow of Prince George, Duke of Kent, passed away hours after the Kensington Palace announced that she was suffering from a brain tumor. She died on August 27, 1968, at age 61.

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William of Gloucester -

Prince William of Gloucester, first cousin of Queen Elizabeth II, died unexpectedly at age 30 during a leisure activity.  

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William of Gloucester -

The prince, who owned several aircraft, competed in different amateur air show competitions. On August 28, 1972, he took part in the Goodyear International Air Trophy Race. His plane crashed shortly after takeoff in front of 30,000 spectators. 

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Baudouin of Belgium - At the end of the military parade on Belgian National Day on July 21, 1993, the royal couple flew to their Spanish residence in Motril. Little did the Belgians know that it would be the last time they would see their king alive.

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Baudouin of Belgium -

Ten days later, on the evening of July 31, the king unexpectedly died of a heart attack while on vacation with his wife, Queen Fabiola. King Baudouin was the longest-reigning monarch of Belgium after King Leopold II. The country was plunged into a period of deep mourning.

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Prince John of the United Kingdom -

Prince John, who was born to King George V and Queen Mary on July 12, 1905, suffered from epilepsy and possibly autism. He is often referred to as the "Forgotten Prince" or the "Lost Prince" due to the fact that he was kept out of the public eye and sent to live at Sandringham House. 

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Prince John of the United Kingdom - He died at age 13 following a severe seizure. His brother, future King Edward VIII, would later say in a letter that John was like "an animal" and that his death was the "greatest relief imaginable" to his family.

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Princess Charlotte Augusta of Wales -

On the evening of November 5, 1817, Princess Charlotte gave birth to a stillborn baby boy. A few hours later, she began vomiting and bleeding, and eventually passed away. She was only 21 years old and was set to become queen one day.

See also: Celebrities you never knew were related to royals

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