It was a day like Toronto has never seen and hoped it never would - a day of smashed windows, burning police cars, police cavalry charges and, for the first time in our history, the whiff of tear gas in the air.
A mob of black-clad "anarchists" roamed unopposed up Yonge Street, howling in triumph every time one of them broke a window with a hammer, brick or garbage can. Hundreds of riot police banging on their shields cleared a mostly peaceful crowd from Queen's Park. Late into the night, police were still confronting knots of roving protesters from the wet and darkened streets.
"Whose streets? Our streets!" yelled the mob as police faced them down. For at least a few scary hours on Saturday, they seemed to be right.
Perhaps we should have expected this. Authorities had warned again and again that hard-core protesters were planning to descend on the city to cause mayhem during the G20.
All the same it was disturbing, even infuriating, to see a small group of militants rampage through downtown on a Saturday afternoon, leaving the city with a black-eye and a sick feeling.
It hurt to see the city come to this - and for so little reason.
Like a householder after a break-in, the city is experiencing a sense of violation mixed with anger at the senselessness of it all.
Even police chief Bill Blair, who had warned that trouble makers were on their way to the city, confessed to being taken aback.
"I have to tell you, I think it was shocking to every citizen and everyone who witnessed the images that were being projected across our television screens," he said. "We have never seen that level of wanton criminality, vandalism and destruction on our streets."
The worst of it was that all this trauma was caused by a small group of perhaps 100 or 200 hard-core militants who broke away from the main protest march from Queen's Park to rove at will around downtown with destruction on their minds.
"This is what democracy looks like," chanted the black-clad mob moving along Queen Street past City Hall as its smashing spree began. No, this is what idiocy looks like. What, many Torontonians were asking, was the point of it all? What kind of people would do something like this?
Scrawling "class war" and "bomb the banks" on windows and walls. Smashing windows of Burger King, Starbucks and Tim Hortons while frightened staff and customers huddled inside. Screaming abuse and hurling rocks at the police trying exercise their duty to maintain order.
"This is wrong," said one passerby who saw black-masked men smash the window of a cell phone shop.
"Why?" shot back a young woman in dreadlocked black hair. "No animals or human were hurt. Look at what the corporations are doing." With a contemptuous look over her shoulder, she walked away, hand in hand with her boyfriend as if on a pleasant weekend stroll.
A few blocks down the street, Howard Dale, a deputy crown attorney who was in the area at the time, was so angry that he took matters into his own hands, grappling with a slight protester in combat pants and black-kerchief who threw a big rock at a window again and again, trying vainly to shatter it.
He told her to put the rock down. When she picked it up again, he grabbed her from behind and wrestled with her.
"We can't just stand around and do nothing," he said afterward, his voice shaking with anger.
There were other acts of bravery. At College Park on the corner of College and Yonge, a lone, grey-haired security guard came out of the building to confront the young men in black hoods who were breaking the window of a Tim Hortons. He brandished a truncheon but had to retreat when the crowd screamed threats and surrounded him.
The police, for the most part, showed restraint, backing off as a throng of a few dozen rioters roamed through the business district then up Yonge Street and along College, smashing all the way.
In fact, some of the same people who complained about all the cops in the streets for the G20 may now be tempted to ask why more wasn't done to control the mayhem-makers. There was not a cop in sight as the crowd went on its rampage on Yonge.
Chief Blair said that police feared the protesters would try to draw them away from the G20 security zone. That may explain why officers did not pursue the protesters on their smashing spree. Better to see some windows broken, they may have reasoned, than engage in running battles between police and protesters that scarred the face of Seattle during the world trade talks there in 1999.
The behaviour of the police, it has to be said, was not always impeccable.
They put on their biggest show of force at Queen's Park late in the day, using mounted police to clear the park around the legislature.
Some spectators said only a cursory, hard-to-hear warning was issued. At least one man was caught under horses' hooves and one woman journalist sustained a welt after a policeman hit her with a truncheon on the hip. Another journalist was hit by what appeared to be a bean-bag bullet, sometimes used for crown control. As the evening drew on, police beating on their riot shields and marching forward in stages cleared protesters and spectators from Queen's Park north - an area that was supposed to be a free protest zone. Chief has yet to explain adequately why that was necessary or justified.
By Sunday morning, nearly 500 people had been arrested, a shocking figure. It may prove that some of those detainees were arrested without cause in the aggressive police sweep that followed Saturday's vandalism.
But the ultimate blame for the weekend's events lies with the violent minority who spoiled what began as a peaceful, even festive protest, destroying property and frightening people in aid of - what?
"It doesn't do any good for any cause - and I don't even think they have one except causing violent acts," said a visibly angry Mayor David Miller. "It's sad for the city that these criminals chose to commit these criminal acts here."
Sad indeed. Toronto has seen scores of protests on any number of issues over the years but Mr. Miller said that this was the first time since a confrontation with anti-poverty protesters at Queen's Park more than a decade ago that we have seen one turn so violent - and this one was far worse. Only the so-called Yonge Street riot of 1992 comes close in recent history.
As Chief Blair confirmed, this was the only time police here have ever been forced to use tear gas in what is, for the most part, a remarkable safe and law-abiding city.
What was especially galling was the glee of the rioters as they made their merry way through the streets. Some of the group took cellphone photos or exchanged victory hugs. Other leapt up and down like madmen on the roofs of abandoned police cars and media vans.
When rioters set a police car on fire, a female protester said into her phone: "Let's get another car! They spent a billon dollars of our money on this. We might as well make them pay."
To call this a mob seems wrong. A mob is a fluid, changeable thing, with spontaneous moods that flare and die. This was much more organized and deliberate than that.
The whole thing had the feeling of a well-practiced game. Rioters knew just what to use to break shatter-proof windows. Some carried hammers and golf balls. Others pried bricks from the sidewalks or used the sticks from their protest banners and placards. Still others picked up folding metal sidewalk signs or newspaper boxes. They attacked the windows with a skill that seemed to come from experience or training.
Indeed, this was a well-organized "mob," with its own legal aides and marshals. There were even first-aid officers calling out "is anybody hurt?" with tender concern after every window shattered.
Fortunately, the chaotic day came to an end with no reports of serious injury. By Sunday morning, shopkeepers and businesses had already replaced many of the broken windows and some were covering their facades with plywood to prevent further damage today.
If the rampage showed how vulnerable big cities can be to this kind of deliberate action, it also showed how robust they are. Life goes on. Even on Saturday night, there was traffic on the streets and people on the sidewalks going about their business.
On Sunday morning, the subway started running again, the Eaton Centre planned to open as usual and things were getting back to normal. Outside of central downtown, most people were unaffected and learned about the events only through the media.
All the same, it hurt to see the city come to this - and for so little reason.