The world was already a troubled place before two airliners slammed into the World Trade Centre's twin towers in New York City on September 11, 2001.
Two other planes crashed that day, one near the Pentagon, the other in a Pennsylvania field.
We knew about terrorists before then. We knew about violence and other human-created disasters. But the deadliest terror attacks in world history, which killed nearly 3000 people and injured more than 6000, stripped us of any remaining innocence about the horrors of cruelty and the dangers of fear.
It could happen in New York. It could happen anywhere. And it has, at the hands of foreign and domestic thugs in places as diverse as Oklahoma City, London, Paris, Christchurch and Auckland.
In another era, way back in November 2019 before Covid-19 gripped the planet, I visited the 9/11 Memorial in New York City.
The plaza's centrepieces are two pools sitting in the footprints of the North and South Tower. Water flows from around the perimeter, on all four sides, cascading about 9m. Another drop lies within the pool, falling an additional nine metres. It's a symbol of the void into which 9/11 victims fell, a marker of loss survivors feel.
I ran my fingers along names engraved in stone. White roses dotted the memorial. Each morning, staff place individual flowers on names of people who would have had a birthday that day.
It is too much to absorb. Too many deaths to comprehend. What do we owe the victims of 9/11? How do we honour their memories?
I'm not sure how we do that on a mass scale. I do know we keep their legacies alive when we speak the names of individuals and share their unique stories.
One Kiwi died in the attacks. Alan Beaven, an environmental lawyer from Auckland, was on flight 93 when it crashed into a Pennsylvania field. Crew and passengers struggled to regain control of the plane and Beaven's remains were found in the cockpit, according to a 2016 NZME article.
His daughter told CNN back then she was studying to become a psychologist to support people through loss and post-traumatic stress. Sonali Beaven said she chose "life and love" every day and refused to let fear or hate hold her back.
Earlier this week, officials announced new technology had helped identify two more victims of the terrorist attacks. According to NPR, Dorothy Morgan of Hempstead, New York, is the 1646th victim to be identified through ongoing DNA analysis of unidentified remains recovered from the World Trade Centre site. The second person's name is being withheld at his family's request.
More than 1100 victims who died on 9/11 remain unidentified.
Anyone old enough to tap their memory banks from 2001 can tell you where they were during 9/11. My late husband and I had just started a three week trip to Europe. We were checking out of our Dublin hotel when the first plane hit the towers.
We drove into the countryside listening to Radio Ireland, as President Mary McAleese expressed shock and horror over the attacks. We couldn't fly home, since planes were grounded. We continued our holiday with guilt and sadness, consoled by people along the way who heard our American accents and expressed condolences.
Then, as now, I felt disconnected between where I am and my home country, an inability to bridge the distance between here and there.
9/11 set the wheels in motion for actions many political experts say fuelled the rise of the Islamic State: The US invasion of Iraq and America's longest war, a 20-year deployment in Afghanistan.
The withdrawal of US troops from the country on August 30 resulted in chaos and the takeover of the Taliban, who the Western world sought to oust in the first place.
The terror attacks fomented fear and prejudice against Muslims. They inspired new laws, more government surveillance and increased airport security. The measures remind us our safety is never assured.
But the tragedy also inspired acts of kindness. People of all faiths and no faith linked arms with their Muslim brothers and sisters in solidarity. We gave blood, made quilts, held bake sales and donated money. We flew flags at half staff, attended vigils and cried for people we didn't know.
The advice for children by longtime American TV show host Fred Rogers was "look for the helpers". The guidance for adults should be more prescriptive - be a helper. Not a vigilante, but someone who listens, tries to understand and shows kindness through words and deeds.
How do we honour the victims of 9/11? In a world marred by violence and acts of ugliness, we work hard to create the beauty we wish to see. Sure, it's messy. And imperfect. A never-ending struggle. But it might be the best we can do.