Yes, the city fathers had expected demonstrations. Yes, they knew it would take a huge police presence to prevent the situation from getting out of control. But the sheer numbers - well over 50,000 people swarming through the city's downtown streets - and the impact of those who smashed their way along one of Seattle's most popular shopping streets and provoked law officers into a showdown with tear gas, pepper spray and rubber bullets, caught just about everyone off guard.
For the demonstrators - everyone from student political activists to environmental warriors, Zapatista rebels from Mexico to militant vegetarians, steelworkers and farmers to elderly women worried about the future of the earth's forests and endangered sea species - Seattle solidified an extraordinary coalition of differing agendas and interest groups into a concerted wall of protest against the prevailing direction of global capitalism.
Many of the protesters were young, either college-age or just a little older, and their actions felt like the first big stab of revolutionary fervour in an age of widespread apathy and aimless alienation. "Apathy is a big problem around the country, but I see this just blowing that out of the water," said Nathan Wessler, a high school student from Maine who flew 3,000 miles across the United States to be a part of a new movement.
"It's cooler to give a crap than it used to be," said Han Shan, spokesman for the Ruckus Society, the Berkley-based agitprop group that helped coordinate the non-violent sit-down protests and the spectacular banner displays organised by trained climbers scaling cranes and retaining walls of Seattle's main motorway.
In the city that gave birth to the grunge movement, the uniforms of this Generation X movement were familiar - plenty of body piercing, loose-fitting clothing scoured from second-hand stores and charity shops, woollen hats and fake leather jackets. But the message they delivered with such force was not.
Their refusal to be ciphers for consumerist society, their concern for environmental standards, for working conditions, for what big agri-business corporations put in their food, for maintaining diversity in a world increasingly dominated by big chains - this was something that had not been expressed with such force since the height of the Vietnam War protests, which took place before most of them were even born.
To pull off such a coup took a remarkable degree of planning. The Direct Action Network, the umbrella organisat- ion that brought a dozen or so groups under its wing on condition that they remain non-violent, has been at work on this week's activities since January, when Seattle was first named as the host for the WTO's so-called Millennium Round of trade negotiations.
Groups within the network such as the Ruckus Society, the Rainforest Action Network and Global Exchange, have held seminars and camps to teach their members the rudiments of civil disobedience techniques, including the fine art of rappelling up and down buildings and methods for confronting riot police for maximum publicity in their favour.
More than the 1960s generation, the Generation X-ers are media-savvy, understanding the power of television or photographic imagery that will epitomise and further their cause. A banner which hung from a crane at the beginning of the week had two arrows with "Democracy" pointing one way and "WTO" pointing the other. On Tuesday, two women danced topless with the slogan, "My body is not a commodity", scrawled on their backs.
Those who carried on looting and smashing late into the night on Tuesday may have been out on a limb, as regards the vast majority of the non- violent demonstrators. Bizarrely, however, their targets were born out of an ideology that many of the majority would have shared.
Originally grounded in the prevailingly gentle liberal philosophy of the American West Coast, the high-profile symbols of the new, highly mobile global capitalism - shops like The Gap, which originated in San Francisco, and homegrown Seattle institutions like Nordstrom's department store and Starbucks coffee - have since turned into conglomerate giants much like the class enemies of old.
Starbucks, for example, began as a corner shop at Seattle's Pike Place Market - the magnificent display of fish, fruit and vegetables that has turned into a major tourist attraction. Now there are so many Starbucks located around the United States that there are often two on the same block.
Anti-WTO demonstrators denounced the company for the origins of its coffee, its hiring and employment practices, to the bewilderment of the Starbucks founder, Howard Schultz, who argued yesterday that he had always tried to keep his expanding empire decent and ethical.
There are, of course, similarities with the 1960s protest generation, and indeed this week's proceedings were watched admiringly by the likes of Tom Hayden, the one-time Yippie who went to jail for organising peaceful demonstrations at the 1968 Democratic Convention in Chicago.
But there is also a deep suspicion of the 1968-ers, not least because many of them have grown up to occupy the positions of power the Generation X-ers now despise. Mike Moore, the WTO's executive director, marched against Vietnam, as did Charlene Barshefsky, the US trade representative.
Part of the reason the protests were allowed to grow so large in Seattle was because the city's mayor, Paul Schell, sympathised with much of what the demonstrators hoped to achieve.
Half of his city council joined the official trade union march on Tuesday afternoon, which marked the most peaceful, best organised part of the entire event.
But by yesterday Mr Schell was being denounced as just another powerful white guy as the Seattle police drew a "no-protest" perimeter around the city's downtown area and moved aggressively to snuff out protests with tear gas and loaded semi-automatic rifles.
The man who perhaps best epitomises the ambivalence the protesters feel about the 1960s generation is Bill Clinton, who was in town yesterday to address the WTO. In an interview in yesterday's Post-Intelligencer, Seattle's morning newspaper, the President expressed sympathy for the demonstrators' agenda and spoke out against child labour and general oppression of workers overseas.
While union leaders praised such sentiments as a welcome change of tone, they were denounced on the streets as a belated attempt to co-opt the protest movement when his real agenda was giving the WTO carte-blanche to determine trade policy on behalf of multinational companies. This perceived insincerity drove much of the fringe violence.
"We don't have time to change things non-violently," said a 17-year-old demonstrator called Rain, who said the protesters of the 1960s were too passive.
"But property destruction is not violence. It's fun and it gets people's attention."