9/11: The day the world shookIt was the most devastating terrorist attack in history, and its repercussions are still being felt today
When two hijacked passenger airliners crashed into the Twin Towers of New York's World Trade Centre on September 11, 2001, the cataclysmic attack created the mood of our present era.
It turned the following years into an age of extremes, and the repercussions are still being felt today.
The editorial in the Irish Independent foresaw that things would never be the same again.
The writer warned that the wrong response to the attack could be "catastrophic".
"It is not enough for the United States to meet force with greater force. Yesterday tested its psyche and ability to hold together. The coming days will test its judgement. On that, more than on its military power, the world depends."
The writer was correct to urge caution. These acts of nihilistic violence were followed by ill-judged interventions by the American Bush administration and the British government in Afghanistan and Iraq.
So many other events have flowed from the attack, directly or indirectly, across America, Europe and the Middle East.
As well as leading to the wars in Afghanistan and Iraq, 9/11 contributed to the conflagration in Syria, and the effects of these conflicts have spilled over into Europe.
Its immediate effect, shocking in its sheer scale, was the death of nearly 3,000 people - including workers in the Twin Towers, plane passengers, and firefighters who rushed into the building, as others tried to escape.
It led to a rise of Islamophobia and the populist right. It encouraged anti-immigrant movements - from the National Front in France to Donald Trump in the United States.
It could be argued that fear of immigration from the Islamic East also boosted the once marginal campaign to bring the UK out of the EU.
On its front page on September 12, the Irish Independent described it as "the most devastating terrorist attack in history".
In recent years, some Islamist attacks have been carried out by so called lone wolves, using crude methods such as driving into crowds and lashing out with knives.
But the September 11 attack was like nothing we have seen before or since. As the Irish Independent put it, "The atrocity was meticulous in its coordination and horrifying in its effect."
The Twin Towers were symbols of American capitalism, close to its financial heart in Manhattan.
Some of the 19 hijackers, including the tactical leader of the attack, Mohammed Atta, had undergone special flight training as pilots in preparation.
The attackers may have been medieval in their attitudes, as they sacrificed their own lives in a futile cause, but they were highly sophisticated in their choice of targets.
They were designed to create the maximum effect, and three of the four airliners hit their intended targets after being turned by hijackers into murderous weapons.
It was late lunchtime in Ireland when news of the disaster began to filter through. At 8.45am New York time (1.45 pm in Ireland) American Airlines Flight 11 crashed into the north tower of the World Trade Centre.
Minutes later, on TV screens across the world, there were live pictures of the burning tower, but there was uncertainty about how the crash had happened. There was some speculation that it could have been an accident.
But, among the throng surrounding the TV set in the newsroom of the Irish Independent on that day, there were gasps of disbelief just a few minutes later when a second aircraft, United Airlines Flight 175, crashed into the south tower.
It immediately became apparent in those chilling moments that this was no accident, and America was under attack. US President George Bush made a TV statement to the people of the United States, saying: "We have had a national tragedy. Two planes have crashed into the World Trade Centre in an apparent terrorist attack on our country."
Within minutes, a third hijacked plane, American Airlines Flight 77, crashed into the US military headquarters, the Pentagon in Washington DC.
A fourth hijacked plane, United Airlines Flight 93, crashed into a field in Pennsylvania. Hijackers had directed the plane towards Washington DC, leading to speculation that their intended target was the White House or the Capitol building. It is believed that the passengers and crew overpowered the hijackers and took control of the plane.
Emergency services rushed to evacuate the towers in scenes of pandemonium, and some desperate figures jumped from the building. As each person leapt, the gathering crowds in the streets screamed.
But within minutes, both towers of the World Trade Centre collapsed resulting in the loss of thousands of lives, including emergency workers and firefighters who had gone into the building to help.
As the Irish Independent report put it, surrounding buildings and thousands of people in the streets below, were covered in a thick coating of dust thrown up by the collapsed towers.
In the hours afterwards, there were feelings of justifiable alarm. There were concerns that this spate of attacks was just beginning, and that the terrorists could strike anywhere at any moment.
In the following day's paper, there was no precise figure on the number of casualties. Families put up signs in Manhattan desperately seeking their loved ones, but within a short time most had to accept that they had perished.
In the days that followed, there was a moving account in the Irish Independent by the novelist Colum McCann of life in New York on September 11, and how the attack affected his family directly. Similar scenes must have played out all across New York and beyond.
McCann was working at home - five miles from the World Trade Centre, and his wife Allison was also at home with the couple's two young children.
The kids were playing on the living room floor with toy train tracks, when McCann picked up an alarmed voice message from his sister in London, concerned about how they all were.
McCann and his wife turned on the TV to see the World Trade Centre ablaze, and immediately their concern was for Allison's father, Roger Hawke, who worked as a lawyer on the 54th floor of one of the towers.
There were frantic phone calls as the family tried to find out what had happened to him. When the second tower collapsed they switched off the television, fearing the worst.
Two hours after the attack, an email finally came through from McCann's mother-in-law: "Your father is okay, thank the Lord. (He) got out of the building minutes before it collapsed. He is walking towards you right now."
When he finally came through the door, after walking the five miles from downtown, McCann's father-in-law took off his shoes, still covered in dirt and debris from the bombing. McCann's daughter Isabella looked up: "Why does grandpa smell of smoke?"
Roger Hawke gave a dramatic first person account of escaping from the tower to the Irish Independent.
"Suddenly, there was a huge bang and the building shook violently, swayed back and forth. I tried to stand but couldn't. Even the windowpanes seemed to bend.
"Outside, there was a storm of debris, papers, concrete, glass falling. I thought immediately it was a terrorist attack and felt sure that the building was going to collapse. I ran out into the hallway and out to the stairwell. The stairs were filled with people, smoke, dust in the air. But it was strangely calm. Very little shouting or screaming.
"We made a space to the right of the stairwell for the injured to get down and the firefighters to ascend.
"The smoke was dense and the floors were treacherous from streams of sprinkler water coming down the stairs. My shoes kept slipping from underneath me. It took well over an hour, maybe 90 minutes, to get near the bottom. When I stepped outside to the plaza, it was unreal.
"Debris, girders, masonry. The air was thick with a blinding white dust-light. It was like stepping into a morning snowstorm."
When the casualty list was drawn up in the days afterwards, and the missing were accounted for, it was found that 2,996 people had been killed and more than 6,000 others wounded.
The deaths included 265 on the four planes, 2,606 in the World Trade Centre and in the surrounding area, and 125 at the Pentagon. The first certified casualty of the September 11 attack was an Irish-American priest, Father Mychal Judge, whose family came from Keshcarrigan, Co Leitrim.
Father Judge, the Franciscan chaplain to the New York City Fire Department, had rushed to the scene.
There he met New York Mayor Rudolph Giuliani who asked him to pray for the city and its victims.
Father Judge followed firemen into the North Tower, where he offered prayers for the rescuers, the injured, and the dead.
He was killed by falling debris in the tower.
Overall, an estimated 1,000 victims who died in the 9/11 attacks had Irish-American links, but just six were born in Ireland.
Among the Irish victims were Galway woman Ann Marie McHugh, who was working on the 84th floor of the South Tower, and Tipperary carpenter Martin Coughlan, who was refurbishing offices in the same tower.
In the Irish Independent on September 12, the attack was immediately linked with the Afghan-based terrorist leader Osama Bin Laden and his al Qaeda militia.
Attacks on his bases in Afghanistan were seen as inevitable.
The resulting war in Afghanistan, which spilled over into Pakistan, led to the deaths of an estimated 150,000 people.
The death toll in the war in Iraq, which has also been linked to the September 11 attack, is estimated at over 250,000. The aftershocks of the 9/11 attack continue until the present, and will still be felt for many years to come.