By Dominic Casciani
BBC News, Belfast
How do you measure peace? Does it come in the number of photographs of IRA guns, the number of jobs created since the ceasefires or something vaguer still, such as physical change?
Christmas market: The sweet smell of normal life
Belfast has been hosting a grand continental Christmas market: French crepes, glorious Willy Wonka-like sweets and fabulous exotic bulbs for winter planting.
So while the Democratic Unionists and Sinn Fein fell out over photos, the market was full of shoppers taking their own snaps of a warming Christmas scene.
The entire policing for the market comprised a few beat officers in baseball caps and their winter woollies: this would have been unthinkable a decade ago.
Depending on who you listen to, Northern Ireland is either the closest it has ever been to a comprehensive settlement or as far away as ever.
And although the latest deal collapsed at the eleventh hour, there are ways to measure the progress of a decade of change.
Pat Colgan knows about this. He is the chief of the European Union body charged with delivering the peace dividend - hundreds of millions of pounds of investment in community projects to keep up the pace of transformation.
As Prime Ministers Tony Blair and Bertie Ahern flew into Belfast to give us their thoughts, Mr Colgan was also in the city talking to 250 community groups about what the money means to them.
Guns: Seen on the murals, but not on film
The "Peace II" programme, as the EU jargon has it, has poured more than £410m into 3,000 projects so far. Eight out of 10 projects have a cross-community foundation.
You can see the physical changes this money has brought in the number of locally-led enterprises that have mushroomed throughout Northern Ireland.
The programme's new research into how this money has affected public attitudes provides another way of trying to measure peace.
According to Peace II, the overwhelming majority don't see the other side as their enemy - something which people who visit Northern Ireland quickly learn.
While nine out of 10 people don't care whether their doctor is Protestant or Catholic, up to 3% of people still do.
But what the research also reveals is that the more people become involved in peace work, even at a superficial level, the more their attitudes change.
So when surveys find almost 10% of those questioned would think twice about selling their home to someone from the other tradition, the proportion is lower among those involved in peace projects.
Dispute over spending
Now, the good news is that there are a lot of projects doing a lot of work - and there is hope for a fresh round of mega-funding from 2006.
But the bad news is that even in this area of Northern Ireland life, there is dispute over how we measure the dividend.
There is a sense among some unionists - particularly at the "interface" areas between the communities that Peace II funding has disproportionately gone to Catholic/nationalist areas and projects.
The Democratic Unionists have complained to Brussels saying it's unacceptable.
This perception is important because time and time again in Northern Ireland disputes have escalated because of suspicions that this community or that get one over the other.
Without a doubt more money has gone into nationalist areas than unionist areas.
But Pat Colgan says the reasons for this are complex and he has repeated appeals for more Protestant/unionist communities to come to them and learn how they can use the money.
"I have discussed this with the political parties and there is a lack of community organisations in certain sections of the Protestant community," says Mr Colgan.
"This has disadvantaged them in some ways. They need to demonstrate 'capacity' to manage this money.
"The lack of structures and organisations within their own communities is behind this problem."
Closer than ever
Peace II is under no illusions about the scale of the problems still facing Northern Ireland - particularly in very poor unionist areas where loyalist paramilitarism remains a power.
But Pat Colgan's message is one of optimism, no matter what the prime ministers had to say.
The gap: We were this close says PM
Back in Belfast city centre, the prime ministers were indeed explaining how close everyone had come to that deal, closer than ever before they said.
Irish Taoseach Bertie Ahern's own measure was that Northern Ireland was on the "brink of an accommodation which would have been considered impossible" just a year ago.
Politics was not as polarised as people thought, the PMs insisted.
But by whatever measure, their 20-page peace plan had come to nothing because of absolute disagreement over paragraph five of page 16: Photographing IRA arms.
So what did people think of those photographs just a few hundred yards away at the Christmas market?
Like many others around Northern Ireland, they had their own measure: the length of their sighs when you asked them what they thought. Just get on with it and get a deal, people said. Nobody reserved any particular ire for either side.
All of them declared they just wanted to get on with their Christmas shopping. A measure of peace indeed.