Crowds have gathered in the US city of Dallas to observe a moment of silence to mark the 50th anniversary of the assassination of President John F Kennedy in the city's Dealey Plaza.
The moment of silence began on Friday at 12:30 pm (1830 GMT), the moment on November 22, 1963 when the fatal shots were fired at Kennedy's motorcade from the Texas School Book Depository by Lee Harvey Oswald.
The young leader's brutal televised death, a dark turning point even in an era gripped by the Cold War nuclear stand-off and bloodshed in the jungles of Vietnam, shocked a global audience of millions.
Five decades on the wound is still raw, with many still obsessed by the conspiracy theories surrounding his death, and others gripped by regret for the America they imagine might have been.
Across the nation, at ceremonies large and small, many took comfort in reflecting upon the words of a charismatic man whose soaring rhetoric and call to service continues to inspire.
"Today, we honour his memory and celebrate his enduring imprint on American history," President Barack Obama declared.
Across the Atlantic too, Kennedy was remembered. A wreath-laying ceremony was planned in the Berlin neighborhood where Kennedy gave his famed Cold War-era "Ich bin ein Berliner" speech to a rapturous crowd.
At Kennedy's tomb in Arlington Cemetery outside Washington, two kilted pipers from the Black Watch of the British army repeated a tribute their regiment had performed at his funeral 50 years ago.
Today and in the decades to come, let us carry his legacy forward.
In a proclamation ordering flags be lowered at government buildings and even private homes, Obama recalled Kennedy's leadership in the Cuban missile crisis, his speech in Berlin and his drive to advance the rights of African Americans and women.
"Today and in the decades to come, let us carry his legacy forward," Obama wrote on Thursday.
"Let us face today's tests by beckoning the spirit he embodied - that fearless, resilient, uniquely American character that has always driven our Nation to defy the odds, write our own destiny, and make the world anew."
In Arlington, a steady stream of mourners visited Kennedy's grave, including his last remaining sibling Jean Kennedy Smith.
"It was a major shock to the world," said Tom Brown, 71, a retired civil servant. "Here we are, 50 years later, and we still remember. We still want to acknowledge him and his presidency."
Student Caitlin Coffey, 22, said she came down from Toronto specifically for the occasion.
"It's just remarkable to think that one person, one family, was able to make such a global difference," she told the AFP news agency.
Kennedy's voice still echoes through history to so many Americans.
"Ask not what your country can do for you; ask what you can do for your country," he urged Americans at his inaugural address on January 20, 1961.
Source: Al Jazeera and agencies