Looking out your apartment window these days, it's hard to tell whether you're in Mexico or L.A. In both places, the affluent young of all races mix so easily the cultures are almost indistinguishable -- it is only when you venture into nearby neighborhoods of poor people that you become aware of a very real class divide. PNS commentator Ruben Martinez is at work on a book about life and death in the borderlands.

I once lived in Mexico City, although I'm not sure. I know I had an apartment on street called Avenida Veracruz, in a middle-class neighborhood called Colonia Condesa. One window looked out on a row of tall jacaranda trees that bloomed lavender in the springtime but looked really depressing when the blossoms and leaves disappeared and the naked branches twisted their way into the wintry smog-sky.

Down the street there's a pool hall owned by a bohemian guy from New England named Kurt Hollander, who happens to publish a bi-national, bilingual art magazine called Poliester. He has a very pretty wife, a Mexican woman, and they have a very pretty baby whose skin glows a shade somewhere between his white and her light brown.

Kurt is tall, dresses in what most cultures would consider rags, and has his head shaved. He plays nothing but 1960s soul at the pool hall; James Brown is always screaming sexily. Every afternoon and evening, the place fills up with kids who look, at least at first, as American as Kurt. They wear rags. They like James Brown. They speak very good English. They are mostly white.

They are all Mexican.

In Mexico, they are middle-class; in the U.S., they'd surely be seen as upper-class. It is not clear whether any of them actually works for a living (the pool hall is often packed on a weekday at 2 pm), or whether they live off allowances from their parents, who basically run Mexico City.

Condesa looks a lot like a neighborhood in another city I also think I once lived in, the Silver Lake district of Los Angeles. There, too, there are pool halls with James Brown soundtracks, and jacaranda trees, and smog.

In Silver Lake, the white twenty-somethings running around are pierced and tattooed, and have lots of sex, increasingly with members of their own gender and with members of other races and ethnicities.

In either Condesa or Silver Lake, it's easy to have sex with someone of a different skin color. In both places there are a lot people in various shades of brown in addition to the whites, as well as Asians and blacks. In and around both neighborhoods, the darker-skinned people tend to live in crowded apartment buildings and run-down houses that the white kids think are cool, and are increasingly moving in to. The landlords are very happy the white kids think poverty is cool, because they can jack up the rents.

In Condesa the movie theater, El Plaza, is playing "Armageddon," the film now showing at the Vista in Silver Lake.

I am not sure if I lived in Silver Lake, or Condesa, or both, or neither, because I'm confused as to which is which.

These neighborhoods are separated by a few thousand miles and by the invisible but implacable boundaries between the "first world" and the "developing world," but they might as well be contiguous. In both places the younger, poorer, brown-skinned kids wear the uniforms of urban warriors -- backwards baseball caps, baggy jeans, name-brand sneakers. The middle-class white kids, not to be left behind, shave their heads like Kurt Hollander, and wear baggies, and talk hard, like the black and brown rappers whose albums they buy.

In my apartment building in Condesa or Silver Lake, some kids lived downstairs. One of them, named Randy, had silky blond hair, blue eyes, a lithe body, and a smirk. Oftentimes at three in the afternoon or at three in the morning, Randy and his friends, inspired by God-knows-what combination of substances, would rehearse their music. Randy is a rapper.

I assumed that Randy was Mexican. Big mistake -- you can't assume anything in Condesa or Silver Lake these days. There was a rumor Randy's father was, or is, an agent for the Drug Enforcement Agency (DEA). That would explain Randy's aesthetic choice -- he and his crew, called Molotov, basically sound like hemp-gangsta' rappers Cypress Hill.

Still, it was quite curious to hear and see, at three in the afternoon or three in the morning, a bevy of young, brown-skinned Mexican girls screaming Randy's name up from the sidewalk, hoping to party, and perhaps seduce, one of Mexico's new pop culture heroes, a gringo from Louisiana enamored of Black-Brown Hip Hop.

Part of me very much wants to belong to Condesa or Silver Lake or both. They're undeniably sexy. But I'm not sure either place is substantial. Sometimes I get the feeling this paradisaical tableau has been imagined into being by the middle class.

Do I have to say that not everyone lives in Silver Lake or Condesa? That, in both places, most dark-skinned people serve the white-skinned people? That the forces of global capital are well aware of the existence of a class of people, who just happen to be mostly non-white who have no way to enjoy the goodies of the information economy -- a class they have written off as expendable?

Next to Condesa is a neighborhood called Colonia Roma. It was almost completely destroyed by the 1985 quake and remains that way, save for its northern end, where elegant Deco buildings are home to some elite families. The southern end of Roma, separated from Condesa only by the four lanes of the city's major north-south boulevard, is a barrio in every sense of the word -- a great and terrible place, at once beautiful and fallen. Chavos banda, the Mexico City version of Chicano-style "cholos," rule the streets. Their parents usually work hard for the middle class on the other side of Insurgentes, fixing plumbing, remodeling, washing clothes and cooking meals.

South-southeast of Silver Lake is a neighborhood called Echo Park. On the tops of its maze of green hills (where "echo" comes from) live mostly white, middle-class families, but the flatlands are barrios that look like Colonia Roma South in every way. There are forlorn kids, with parents at their wits' end working to make a future for those kids. There are drugs and there is violence. The immigrant families of Echo Park serve the yuppies of Silver Lake their meals, clean their homes, change their kids' diapers.

All this sexy multiculturalism often obscures deeper class divisions. The world is rapidly changing and there is plenty to celebrate in the new shared spaces of inter-culture. In the movie Bulworth, Warren Beatty proposed that intimacy across racial and ethnic lines will eventually wipe away the legacy of racism (how can you hate or fear the Other when they're lying in bed next to you?), and that class inequity would be faced down by a mixed-race front.

Perhaps all that will come to pass. But it is much easier to be optimistic about that prospect when one lives in Condesa, not Roma South, or in Silver Lake, not the flatlands of Echo Park.