The presidency of John F Kennedy was a landmark event of the 20th century, but the story of the entire Kennedy dynasty is an American fairytale with glamour, privilege and great wealth.
Hugely ambitious and dangerously reckless, the Kennedys have also been blighted by tragedy.
JFK's image was enhanced by Jackie
President Kennedy was assassinated, as was his brother Robert. Another sister and brother died in accidents, as did JFK's son and heir John Kennedy Jnr.
Many question whether the Kennedy family suffers from a strange curse, or whether they are simply the architects of their own tragic history.
Throughout my life I have been fascinated by the Kennedys. I wanted to know what makes them tick, what are the Kennedy traits that made the family so successful, and why have they suffered such misfortune?
Wealth and stealth
Their story begins with JFK's father Joseph Kennedy, the son of an Irish Catholic immigrant family.
Joseph was a canny rogue who became one of the richest men in America during the 1920s and 30s, making a fortune on Wall St, in Hollywood and from bootlegging during prohibition.
Despite his wealth, Joseph was kept at arms length by the American Protestant elite. Joseph decided that if he could not gain access to high society by birth, he would have to do it by wealth and political stealth.
Eventually he resolved that either he, or one of his sons, would attain high office and become the first Irish Catholic president of the United States.
Initially Joseph thought he could become president. He was ambassador to Britain during World War II.
But he argued that America should stay out of the war and was thrown out of government.
All his ambitions were transferred to his eldest son and namesake Joe Jr, but he was killed after volunteering for an heroic secret mission.
After the war JFK picked-up the political baton and became a senator.
He had brains, good looks, political prowess and all the financial backing he needed.
His image as the perfect politician was complete when he married society beauty Jacqueline Bouvier, and he quickly ran for the presidency.
JFK seduced America with his smile and charm while his father shored up political support.
Many believe he did deals with the Mafia to bolster support in key districts.
G Robert Blakey, a former lawyer for the Justice Department, claims to have read transcripts from illegal intelligence wiretaps which cast doubt on the legitimacy of Kennedy's election campaign.
But in 1960 JFK was elected the first Catholic president of the United States at the age of 43.
It was an extraordinary achievement for the entire Kennedy clan.
Never before and seldom since has anyone made politics and the process of government seem so exciting and glamorous.
With his sterling intellect, inspirational leadership, and rare visionary rhetoric, Kennedy offered a brighter future for all mankind.
But there was a darker side to the presidency.
Rumours soon emerged of JFK's rampant womanising.
"He learnt this at his father's knee," says Robert Dallek, JFK's biographer. "His father was a world class philanderer."
"I remember when he met with [British Prime Minister] Harold Macmillan," says Hugh Sidey from Time magazine, who knew the president well and skinny-dipped with him in the White House swimming pool.
"Apparently he told Macmillan he had to have sex every day or he got a headache."
President Kennedy conducted any number of risky affairs while dealing with major political crises, including the Bay of Pigs fiasco when US-backed rebels were caught invading Communist Cuba, and the Cuban Missile Crisis, when the world teetered on the brink of Armageddon.
But Kennedy helped create these crises because he could not bear the idea of Cuban leader Fidel Castro thumbing his nose at him.
Kennedy saved the world several times, but before he could complete his term in office he was gunned-down in Dallas, and his brother Bobby became the head of the family.
Back from the dead?
Bobby followed in his brother's footsteps, and in 1968 he ran for the Democratic presidential nomination, campaigning bravely for African-Americans and downtrodden immigrant workers.
Another Kennedy returning to frontline politics should have raised security concerns, but Bobby refused to accept protection. He was also murdered.
Younger brother Senator Edward Kennedy became the family patriarch, but 13 months after Bobby's assassination, police found the dead body of a young woman in the back of Ted Kennedy's car after he apparently drove off a bridge.
In 1979 Teddy ran for the Democratic Presidential nomination. He was dogged by memories of the car accident, and failed to regain the political throne. The Kennedy dream began to fade.
So America turned to the next generation. JFK's only son, John Jnr, a magazine publisher proclaimed the sexiest man in the world, seemed destined for high political office.
In July 1999 John Jr demonstrated the family penchant for risk-taking and adventure, and piloted his glamorous wife and her sister on a flight others warned him against.
They vanished in a storm over Martha's Vineyard, near the Kennedy family home.
There were other accidents, scandals and tragedies, but the death of JFK Jr was the final body-blow to the Kennedy clan.
"The Kennedy's thought they could rule the world," said John Davis, cousin of Jackie Kennedy.
"But I don't think the Kennedys will ever come back to life. There's not much to them anymore."
Clearly the Kennedy family have taken risks and done things other people are unable or afraid to do.
Because of this they believed they could ignore the same rules as everybody else.
But despite their arrogance, the Kennedys are an amazing, inspirational family who have a strong belief in public service.
The Kennedys brought passion to politics.
Simon Reeve is the author of The New Jackals: Ramzi Yousef, Osama bin Laden and the future of terrorism, and One Day in September: the story of the 1972 Munich Olympics massacre.
His documentary The Third Degree: the Kennedy Dynasty, was broadcast on Thursday, 20 November at 2100 GMT on BBC Three.