This is art on a massive scale: more Brazilians will go and see the exhibition over its two-month run than the best supported football club receives over a whole season.
With Vienna and Documenta in Kassel, the Bienal makes up the three most important large-scale exhibitions in the world - a display of the greatest contemporary creations from across five continents.
Some works are big and dramatic. An elephant with a tiger on its back. A naked painted woman shrieks and sings atop an enormous metal tripod.
A red Volkswagen Beetle is suspended on colourful ropes swinging around in front of a shimmering curtain of silver. There's an upside-down boat, a giant tower of multicoloured lights, and a plane made of knives, scissors and pen knives.
Others are subtle and sublime. For the curator, German Alfons Hug, it is important that the immediate meaning is not made clear.
Car suspended by ropes in front
of a shimmering silver curtain
"Art is not science where there is just one truth. In art there are several and sometimes contradictory truths," he said.
"It is always political, the artist is a citizen just like us and he lives in the same conflicts and he is confronted with the same devastations that we are confronted wit.
"But rather than using reportage or documentary method, he usually works with metaphors and symbols and creates something else out of the earthly raw materials that he finds in this world. So you would never expect an artist just to be reportage. I think it is a mistake."
No man's land
Hug has taken 155 artists from 35 countries under the theme of "free territory", or "no man's land". The exhibits are all under one roof in the gigantic Pavilion designed by the Brazilian architect Oscar Niemeyer that was originally conceived as a trade fair for heavy machinery. But it has been the venue since the inaugural event in 1952.
The Bienal is a landmark in the
life of Brazil's main metropolis
"I invited 80 artists. Curating is basically thinking, reading, studying and travelling. The way I work, you see a work, no matter who, no matter where and it makes some lasting impact. If six months later it still says something to you, it is a good bet that you will invite them," says Hug.
"Outside the centres like New York, London, Berlin, Paris, the so-called periphery has improved greatly during the last few years I see an upsurge in quality in places like Ecuador, Bolivia, the Arabian Gulf. We brought an artist from the UAE, who isn't painting the war as you might expect but paints his landscape. He lives in a house in the mountains by the Omani border, " says Hug.
"Literally there are no white spots anymore on the mapa mundi of world art. And that is one of the encouraging things. The Bienals themselves (there are now 50 across the world) have contributed in bringing the periphery closer," he says.
Brazil's President, Luiz Inacio Lula da Silva, in a last-minute decision to attend the opening ceremony, chose to underline the importance of the liberty of free expression.
Culture Minister Gilberto Gil said, "The Bienal is in the heart of the city. And in the heart of its citizens. It is a landmark in the life of Brazil's main metropolis, a synthesis and metaphor of the best, and the worst, in the nation."
Alfons Hug says the Bienal will show "how the devastations of the real world are reflected in art." He gives examples: 80% of Caracas, Venezuela, is illegally inhabited; entire districts of Rio de Janeiro are extra-territorial zones cut off from state jurisdiction; in deserted highrise buildings and beneath freeway bridges, craftsmen have settled in semi-nomadic conditions.
One Brazilian artist, Rosana Palazyan, has brought some of the words of those worlds inside the exhibition. A man stands turning a musical box, above which sits a real parrot in a cage. The parrot picks a folded piece of paper from a stack in front of it.
Some works are big and dramatic
but others are subtle and sublime
"I spent many months in the streets of Sao Paulo, with homeless people talking with them. The words on the paper are their words. This is called a 'realejo' and is a popular folklore that you can still find in the streets, which tells your fortune. Only this time it is different. All my work is something simple and something strong at the same time," she says.
This year there will be a major systematic programme of guided tours to introduce contemporary art to a whole generation of pupils and students, including many from the favelas, or slums, of Sao Paulo.
And for the first time, entrance is free, with the idea that people can visit and revisit the bewildering array of painting, sculpture and installations laid out across a cavernous 25,000 square metres.
O Realejo is an unusual work of
Brazilian artist Rosana Palazyan
Alfons Hug singles out the reconstruction of Paulo Brucksy's studio at the Bienal, a Brazilian artist based in Recife in the northeast.
His entire flat and it's contents have been moved in as an installation as if frozen in time, from a floor filled in a mess of books and folders to empty beer cans by the kitchen sink.
Hug says Bruscky's library and correspondence with the art world is almost as large of that of the Bienal's.
"I went to see his studio in January and we said 'let's bring the whole studio down here'. He's swamping this whole place with his documents that at one stage got out of control and is now scattered across the floor," Hug said.
"I have the idea that he will never be able to bring order to this. It's like a critique of documentation and science and wealth of information that nobody is no longer able to digest. Art slows down the hype of modern society."
Alfons Hug: Art is not science
where there is just one truth
Hug said, "I hope this Bienal will be remembered for its poetry and beauty. A lot of the works are simply beautiful. The last Bienal had more edge and was more cruel because it was dealing with the critical mass of the modern metropolis, but for me it was too close to reality and that is something we must avoid, always."
"Reality is the big enemy, right?" he added, only half in jest.