JFK anniversary: US remembers "day when hope died" TENS of thousands of Americans gathered at sombre services across the United States yesterday to mark the 50th anniversary of the assassination of President John Fitzgerald Kennedy. At Dealey Plaza, the first official remembrance to take place in Dallas since the world-changing events there half a century ago, a minute's silence was held at 12:30pm, the exact moment that bullets fired from a sixth-floor window of the Texas School Book Depository struck Kennedy in his open-topped limousine. Only 5,000 tickets were available for the ceremony, but thousands more people filled the streets close to the famous plaza on a gloomy morning to watch on giant television screens and pay their respects. "It's an opportunity to mark an occasion that is a moment important in American history, in world history, but doing it in a way in which we can reflect on President Kennedy's legacy," said Ron Kirk, a former Dallas mayor and a member of the 50th anniversary commemorative foundation that organised the event. What we wanted was a very dignified and very respectful service. President Barack Obama, who laid a wreath on at Kennedy's grave in Virginia's Arlington National Cemetery on Wednesday, ordered flags on public buildings across the country be flown at half-mast throughout the day to mark the occasion. "With broad vision and soaring but sober idealism, President John F Kennedy had called a generation to service and summoned a nation to greatness," Mr Obama said in a proclamation for an official day of remembrance. Today, we honour his memory and celebrate his enduring imprint on American history. While President Kennedy's life was tragically cut short, his vision lives on in the generations he inspired. In Boston, the late president's hometown, visitors were cleared from the John F Kennedy Library and Museum for a concert, featuring jazz music by a group first invited to play at the White House by the First Lady, Jackie Kennedy, in 1962. The museum is hosting a temporary anniversary display of artefacts from the assassination and its aftermath, including the American flag draped over Kennedy's coffin at his funeral. Its executive director Thomas Putnam said the organising committee wanted the commemoration to be upbeat. He said: "It's 50 years later and it's also a moment to look forward to the future. We want our tone to be respectful and we want it to have a certain reverence, but we also want it to be hopeful and end on this notion of what JFK stood for. Earlier, at Arlington, Texas, the murdered president's last surviving sibling, Jean Kennedy Smith, 85, joined other family members to lay her own wreath in honour of her brother. Absent from yesterday's commemorations was Caroline Kennedy, 55, the sole survivor of Kennedy's four children, who took up position as US ambassador to Japan last week. Many historians believe Kennedy's death marked the end of an era of hope in American and world politics, despite the challenges of the Cold War. A CNN poll this week gave him a retrospective 90 per cent approval rate, a sharp difference to Mr Obama's current figure of 37. "This is a very polarised era we live in today and people pine for the kind of bi-partisanship that did exist, at least in key moments, back in the 1960s," said Larry Sabato, director of the Centre for Politics at the University of Virginia. None of the ceremonies mentioned Lee Harvey Oswald, the former marine and accused assassin who was shot dead on 24 November 1963 by nightclub owner Jack Ruby in the basement of Dallas police headquarters.