Noam Chomsky will give the forum's keynote speech

Activists have come from around the world for the conference, which was held for the first time last year.

But this year the organisers are distancing themselves from the more violent protests that have typified world economic summits in recent years.

The forum opened with a display of dancing, music and speeches against what many here see as the spread of unbridled capitalism across the world.

Festive atmosphere

The atmosphere so far has been festive. Police are evident but not in riot gear and there has been no hint of violence.

While the forum grew out of violent protests in Seattle, Prague, and, last year, Canada and Italy, its organisers are now insisting that the movement is peaceful.

Anti-globalisation protests prompted activists to hold their own meeting

Guerrilla groups like the FARC in Colombia and the Basque separatists ETA are not attending.

Some anarchists had threatened to hold their own counter-protests but so far they have not been in evidence.

At the next four days of conferences and workshops, much of the discussion will be how to stop a hemisphere-wide free trade deal which Washington is keen to implement.

But perhaps top of the agenda is a nascent peace movement which argues that the 11 September attacks in New York were the result of US and European domination of a world in which the wealth gap is growing and where more and more people are excluded by poverty.

The US linguistics professor and writer, Noam Chomsky, will give the forum's keynote speech, arguing that a world without wars is possible.