Here's a proposition for you: A work of art means something different when there's a whiff of sewage in the air. It's not an idea you're likely to have entertained, unless you've visited the Havana biennial of contemporary art, whose eighth edition opened two weeks ago.

Most of the time, art's meanings shift only subtly when it gets shown in a new context. But Havana is such a strange, fascinating, bewildering place that almost any art shown here seems to come unmoored. The city's stunning contradictions -- fervent creativity coupled with heavy-handed politics; grand historic buildings housing sewage-scented poverty -- force their way into your consciousness as you try to contemplate this exhibition's art.

The biennial was organized by state-approved curators, working on a shoestring budget after foreign funders pulled out in protest of Fidel Castro's latest human rights abuses. (There were also allegations of censorship and interference in the art made for the show.)

Despite the cuts, the organizers managed to pull in close to 150 local and international artists, mostly from the developing world, and give them lavish space to display their wares. The result was a show with many surprising highs -- the best works rivaled anything at high-end art events like Germany's Documenta exhibition or the Venice or Whitney biennials -- and some numbing lows. And both highs and lows read differently because of the city that surrounded them.

Counting up my favorites, I arrived at almost 30 works that really seemed to mean something to me -- maybe a record number for such an exhibition -- and that seemed completely up to speed with the international vanguard. But why go through the hassles of a trip to Cuba only to see art that you could find elsewhere? After a week spent in the sprawling show, however, it became clear that the works themselves, for all their international cachet, meant more here than they would have in other settings.

A large part of the biennial has been installed in former ammunition vaults and prison cells and barracks in the Colonial fortress of La Cabana. When you approach the massive fortifications, the first thing you see is a row of international flags, such as you'd find at government sites around the world. But here in Havana, young Cuban artist Wilfredo Prieto has put a subtle spin on them. He's left the flags' official sizes and patterns absolutely unchanged, but had them manufactured only in shades of gray. The bright blue sky of a hot Cuban November still shines true, but the red, white and blue of French and U.S. flags, the red-on-white of Japan and Canada, the green and red of Italy, now flap against that blue sky in black and white.

There's a striking visual effect to what Prieto's done that anyone could read: A moving, wind-blown chunk of the real world comes to look like a manipulated photograph -- like a photo from the cover of a World Bank annual report, say, as tweaked by a designer who knows the most basic moves in Photoshop.

There's a generalized political effect as well, one that has meaning all around the planet. Crucial symbols of international difference and political identity have been bleached and disempowered. Prieto's move could be read as a sign of optimistic one-worldism. Or it could be a cynical rejection of differences among nation-states, asserting that one is as bad as the next, and that none deserves colorful celebration.

But in the very specific context of Cuba, where politics and international affairs are pervasive forces, Prieto's work takes on a specificity and urgency that it wouldn't have in Venice or New York. Titled "Apolitical," it seems to stand for the deliberate neutrality that Cuban artists and intellectuals are tempted to adopt in order to survive, draining their work of explicit politics until they risk becoming tame studies in composition. And yet, of course, by pointing out that very phenomenon, Prieto's piece itself is far from apolitical. Its apparent neutrality is in fact heavily charged, but ambiguous enough to get past the censors and keep the artist out of jail.

The fascinating ambiguity of Prieto's piece seems to be a hallmark of Cuban contemporary art. It makes the Cuban works some of the very best in the biennial. Cuba's art outshines the truly neutral, politically unconscious work that some foreign artists have on show. It also outguns the strident, message-driven works of other artists from abroad. A nation of 11 million people has somehow managed to turn out far more than its fair share of talented creators. (Excellent education may have something to do with it. A visit to the main art school showed student work as good as you'd get anywhere, even in relatively newfangled fields such as performance and video art.)

Another favorite work in the biennial was by Liset Castillo, born in Cuba in 1974. She is presenting large-scale aerial photographs of expressways and off-ramps and cloverleafs and other major highway projects. Except that, on closer examination, you see that the public works were in fact only tiny models immaculately molded out of sand -- not sand castles, but sand turnpikes. They have all the appeal of perfectly made sand castles: Wonder at the craft that went into them (we've all tried, and failed, to make sand obey our wishes); at their ephemerality; at the simple, unlikely beauty of their sleek forms. But they also have a political poignancy to them in a land where grand government projects often come to naught. Bone-jarring potholes are more prominent in Cuba than expanses of pristine pavement. And yet Castillo's photos don't register as a simple protest at what's lacking. They have an almost utopian wistfulness, too, for what could be, in a country that has all the signs of high culture and education, but few of their usual material rewards.

The Cuban love of subtlety and ambiguity also seems to have governed the selection of work by certain foreigners at the biennial. Alejandro Diaz, a New Yorker of Mexican extraction, is the only American to show work in the exhibition. (A handful of others will be participating in upcoming performance art events). And Diaz's contribution, though clearly politically tinged, has a Cuban-style multiplicity of meaning.

Diaz took some classic red-and-white striped beach balls, as well as white vinyl tote bags, and then had an "I {heart} CUBA" logo printed on each one. On the surface Diaz's work looks like a simple tourist valentine sent to a winning place and people -- but coming from an American, and from the wily world of art, it has a pile of alternative readings as well.

It infects a communist country with U.S.-style marketing, in a kind of foretaste of what might happen if economic relations between the two countries were to change. (It's a delightful irony, well appreciated by Diaz, that the artist's day job is in the marketing department of Estee Lauder.)

Handed out free by Diaz from the stacks on show in his installation, the bags and balls also provided ordinary Cubans with a taste of the tacky capitalist opulence that they can't get at home, since they are refused admission to the foreign-run resorts beginning to clog their beaches. (In a lovely twist, Diaz has discovered that impoverished, entrepreneurial Cubans are reselling his works to foreigners for 30 or 40 bucks a pop.)

Carried on the streets of Miami by an anti-Castro emigre, Diaz's vinyl bag could indicate a love of Cuba as a native land, and an insistence that it should throw off communism and become as American in spirit as New York, source of its logo design.

Proudly borne aloft on Capitol Hill, a Diaz tote could also be used as a standard for the pro-Castro crowd, allowing Americans of the far left to assert their support for Fidel's radical alternative -- as lovable, to them, as the Empire State.

Everything about Cuba, and its relations with the outside world, is vexed. Diaz's deadpan project takes that vexation and runs with it.

It starts as a formal installation, and moves on from there to find a larger audience. Some other artists in the show left the exhibition spaces altogether, to carry art directly to the people. (The biennial's official theme was "El arte con la vida" -- roughly "Art and life as one.")

There is a program of performance art, assembled by a Cuban group with the mocking, pseudo-bureaucratic title of the Department of Public Interventions, that turns the streets into its gallery.

Irish artist Vanessa O'Reilly, who typically works with water, built little temporary electric fountains to enliven a crowded housing complex. She had to cooperate closely with the residents, who husband both water and electricity as precious resources, in order to rework her projects so that they could function in their new Cuban context. Both artist and residents declared themselves pleased with the results of their unusual collaboration.

Another group of artists set up free toilet paper dispensers on one of the dirtiest street corners in Havana, as an anonymous gesture of generosity in a city where public bathrooms don't come equipped with anything beyond the toilet itself. (Sinks and even toilet seats are at best optional equipment; paper products of any kind are unheard of.) A video of the reactions of passersby to the free supply of tissue is both hilarious and poignant.

Other artists were invited by biennial curators to "intervene" in the tiny concrete apartments of the run-down suburb of Alamar, so that the exhibition could reach into the homes of ordinary Cubans. Working in consultation and collaboration with the apartments' occupants, they decorated and painted and restyled their rooms as a kind of domestic installation art. The results were mostly pretty weak, in strictly artistic terms. But that hardly mattered. What made the projects worthwhile was the open-minded, open-armed embrace of art by a segment of the public that in other countries would have been ignored by the vanguard, and would have been happy to be so. In Europe and North America, installation and performance art tends to be the province of the most rarefied art-world elite, and the object of scorn and suspicion from almost everybody else. The so-called "masses" opt for traditionally pretty pictures every time. In the confused streets of Havana, where just coping with the absurdities of an almost broken system requires a kind of daily performance artistry, radical, even absurdist art seems to intervene in life with an authenticity it almost never achieves elsewhere.

In fact, during the biennial, art seems to creep into every corner of Havana. The official biennial events are supplemented by a huge roster of independent shows in artists' studios, private houses and even hanging from the rafters in a meager farmers market.

Go into the quiet, ivy-clad courtyard of one ancient Old Havana building -- careful where you step in the impoverished streets that lead you there -- and you come across a gleaming black Chrysler that has survived intact from the 1950s, only to have a pair of airplane wings, exquisitely crafted and finished to match the car itself, grafted onto its roof by well-known local artist Esterio Segura. Of course, by cynical First World standards the symbolism isn't exactly subtle. But in Cuba, home of transcendent jury-rigging and hopes that refuse to stay earthbound, it has a poignancy that makes it resonate.

The Havana Biennial continues in venues across the city through Dec. 1. Visit bienalhabana.org for information, images and Spanish commentary.

A Cuban woman with one of the tote bags that New York's Alejandro Diaz gave away -- after imprinting them with a classically American commercial logo.Works that mean more in Cuba than elsewhere: Wilfredo Prieto's "Apolitico" bleaches color from various nations' flags. Left, a photo from the "Nail" series by Puerto Rican Rosa Irigoyen. Above, a former fortress and jail provides an apt setting for "Intolerance," an installation by Brazil's Siron Franco; left, one of Cuban artist Liset Castillo's "aerial" photos of expressways (actually models molded out of sand); below, Havana's Esterio Segura, not an official participant in the biennial, grafted airplane wings onto a 1950s Chrysler.