The guide had just finished leading us around the haunting artifacts inside the 9/11 Memorial Museum, which has just opened deep in the bedrock of New York City, when he offered up this idea: a museum doesn't tell you what to think, but what to think about.
After a few hours in this sombre and profound space, punctuated by everything from mangled girders and a crumpled NYC fire truck to eyeglasses found in the debris after the attacks on the World Trade Center, there is certainly much to think about.
What is the best way to remember Sept. 11, 2001, and all that has happened since?
What would those family members who lost husbands, wives, fathers, mothers, sons, daughters, brothers or sisters be thinking if they were here, in this museum carved into the site where their loved ones died?
What about those who tried — mostly in vain — to help; or those who survived?
Everyone has a 9/11 story. For those who knew someone whose life was lost, it is a tragic one that tends to make any other thought of that fateful day pale in significance.
For others, the links are more tangential. But most people remember where they were when they heard planes had been hijacked and fatally crashed into the twin towers of the World Trade Center, the Pentagon in Washington and a Pennsylvania field.
Sixteen months before the attacks, I stood on top of the South Tower, a carefree tourist mesmerized by the stunning view 110 storeys above Lower Manhattan.
On 9/11, I was a tourist in the U.S. again, this time touring Pennsylvania Dutch country at around the same time United Airlines Flight 93 would have passed overhead, the passengers at that very moment plotting to seize back control before the jet crashed near Shanksville.
Now, nearly 13 years later, I found myself a tourist once more, among so many others at the newly opened 9/11 museum, the large crowds making the visit an occasionally frustrating ordeal rather than the moment of reflection and learning it would like to be.
The descent into confusion
For all the bustle, there is still much to see, perhaps more than anyone can take in during one visit to the $700-million, 110,000-square-foot museum that lies in the footprint of the World Trade Center site.
Much careful thought obviously went into finding ways to tell the 9/11 story from so many angles and perspectives, beginning with a large photo showing how lovely and clear that day dawned on New York City.
The museum visitor walks slowly downward in virtual darkness, the way punctuated by recorded voices reflecting the shock and confusion of those first moments after the planes struck the towers.
Twenty metres below street level is the main museum with its historical exhibition and memorial hall. There, each person who died on Sept. 11, along with those killed in the 1993 World Trade Center bombing, is remembered.
The memoriam is a provocative and emotional space, offering voices from victims' loved ones telling something of the lives of the nearly 3,000 people, including 24 Canadians, who died in the attacks.
The pictures on the "Wall of Faces," often happy and taken perhaps from family wedding photos or celebrations, are an emotional punch that captures the enormity of the loss.
That same reaction comes through as well in the stories told by the artifacts, large and small.
Some of those stories feel deeply personal — imagine what it was like to be the person who once wore the simple wire-rimmed glasses found in the rubble.
Or what it was like to be New York Police Department officer Moira Smith, whose damaged nameplate survived, but she did not.
There is the crumpled Ladder Company 3 truck, which took 11 firefighters to the World Trade Center. None came home.
There's the chunk of the broadcasting antenna that stood on top of the North Tower. Nearby is the picture of a man who was working on the antenna the day of the attack.
There was no way to save him. What would he have thought, in the moments after the first plane struck?
Tissue boxes at hand
Depending on how deeply a visitor wants to go into the experiences of 9/11, there's an alcove with voices of cellphone calls made from one of the hijacked planes.
There are also photos of people who jumped from the upper floors of the towers, although somehow I missed that display, and maybe that's just as well.
There are the concrete "Survivors' Stairs" that hundreds of people were able to use to find their way to safety.
And there is much emphasis on those who tried to help, the first responders who lost their lives, and those who survived.
Plus there is homage to the outpouring of support that came into New York from elsewhere in the U.S. and beyond.
What to think about al-Qaeda?
As personal as the museum is, it is also political, and in that way the museum leans toward telling the visitor what to think, rather than what to think about.
Pictures of the hijackers are displayed, discreetly. Attention is paid to the roots of al-Qaeda and missed intelligence opportunities. In a remoter area of the massive Foundation Hall exhibition space, there's a controversial inclusion: a brick from the compound in Pakistan where Osama bin Laden was killed by U.S. special forces in 2011.
"For many, the brick represents the fall of bin Laden's reign of terror; a storied piece of solitary rubble denoting renewal of life in a world in which he no longer remains at large," Alex Drakakis, the 9/11 Memorial Museum's assistant curator of collections, says on the museum's website.
Any museum is a result of choices made of what to display, and what to leave out.
Along the way, planning for this one was fraught, particularly around the emotional and understandable concerns of victims' families. Some were also particularly incensed by some items initially offered in the gift shop. The much-criticized cheeseplate shaped like the continental U.S. has been taken off the shelves.
There is still much unease among some families directly connected to 9/11, particularly because unidentified remains lie within the site, off limits to the public.
"People will find moments of grace or enlightenment or even peace from coming here, I don't need to be one of them," Steve Kandell, whose sister died on 9/11, wrote on BuzzFeed after touring the museum last month.
"I'll probably bring my son one day once I realize I won't have the words to explain. It can be of use. It's fine. I don't know," he said.
Some observers have argued it's too soon or inappropriate to have a museum at the 9/11 site.
But even if time eventually changes the perspective cast on what happened and why, the insight the museum offers today is invaluable as a starting point for assessing the influences that led to 9/11 and what lessons may have been learned for the future.
When I had descended into the museum earlier this month, it had been bright and sunny outside, crowds jostling everywhere. When I came back up into the light and ventured outside, to the poignant and beautiful 9/11 memorial that sits on top of the museum, a torrential downpour had chased all the tourists away.
I gazed into one of the two graceful memorial pools that fill the former base of the towers.
Names of those who lost their lives are engraved into the walls around the pools, arranged not in some sterile alphabetical way, but by association and how victims would have known one another.