Switzerland has sent a 30-strong delegation to the World Social Forum (WSF) meeting - where the new Brazilian president, Luiz Inacio Lula da Silva, spoke on Friday.
Lula promised the Forum, which is taking in Porto Alegre, that he would never abandon his socialist roots.
"A new world order is needed that gives all children, no matter where they live, the right to food and to life," Lula said.
Lula, who flew in the Swiss resort of Davos for the World Economic Forum on Saturday, expressed his commitment to peace and social justice to the 100,000-strong crowd at Porto Alegre.
Although he criticised rich countries for failing to alleviate world poverty, he said corrupt South American countries also shared the blame.
He vowed to tell delegates at Davos that the current economic systems were not improving poverty and starvation.
"I will tell them that it is not possible to continue with an economic system in which some people don't eat three meals a day," he told the crowd.
Set up to debate other means of globalisation, which respect human rights and democracy, the WSF meeting is now in its third year.
The forum is billed as an alternative to the World Economic Forum's annual summit, which is taking place in the Swiss alpine resort of Davos.
A huge demonstration marked the opening of the event, with thousands marching in protest against a range of issues. But everyone seemed to agree on one point: no war in Iraq.
Police estimated that at least 43,000 people took part in the opening march, far less than the 70,000 turnout predicted by the WSF.
Protesters had already overrun the square in front of the central market two hours before the demonstration began, brandishing flags from all around the world.
South American revolutionary music and fiery speeches blared from loud speakers.
Demonstrators protested against a broad range of social evils: land for the landless, respect for human rights, better working conditions in call centres and independence for southern Sahara from Morocco.
"It's enormously varied and vibrant, harnessing feelings and emotions," said Rudolf Stram, a Swiss parliamentarian from the Social Democratic Party. "It is a huge contrast to the cold, manager-orientated capitalism in Davos."
In contrast to the army helicopters patrolling the air space above the Swiss mountain resort, the only helicopter flying over Porto Alegre belonged to a television station.
"WSF is a huge event for the Brazilian media," explained Rafael Monacu, an executive from a Sao Paulo-based channel.
And, unlike Davos, there were no water cannons in sight.
"I have not seen a single water cannon," said Gabrielle Andina of the Social Democratic Party. "That proves that when the population is not misinformed, thousands of anti-globalisation protesters can gather in a town and everything can be peaceful."
Demonstrators said the police were taking a tolerant view of younger, drug-taking protesters and were instead clamping down on drug-dealers.
"The police are here to protect us and that is what they are doing," said law student André Fayermann.
swissinfo, Phillipe Kropf (translated by Faryal Mirza)
Set up in 2000, the WSJ is billed as an alternative to the World Economic Forum.
The issues debated range from the prospect of war in Iraq to improving conditions in developing countries.
Some 43,000 people took part in this year's opening march.
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