TIJUANA, MEXICO — We walk single-file between the thick corrugated metal wall and the highway just a few feet to our left. The sky is grey and hundreds of white crosses line the fence, bearing the names of immigrants who died attempting to reach the "American Dream" on the other side. We read the names of those who did not make it. We peer through a small hole in the wall at the next line of defenses, even more fortified, towering 20-feet-high and lined with meshed wire. In between is a no-man's-land — an eerie terrain recalling a WWI battlefield — except that this is our own backyard. Patches of grass break the sand and gravel. A row of giant concrete pillars supports stadium lights that illuminate the land by night. Thirty feet from us, a border patrol car, white with green stripes, sits quietly... waiting.

We return to our nondescript 15-passanger van and crawl inside. Jackie turns to me. "My parents crossed this very same border," she says. "My dad did it three times. What if they hadn't made it? What if they had died? I wouldn't be here."

Jackie is a senior at Leadership High, a charter school in San Francisco. She has come to Tijuana, on the US/Mexico border, with a group of fellow students as part of their school's "Week Without Walls" program. Their teacher, Melanie Manuel, organized the trip with the human rights group Global Exchange. I am on board as chaperon, keeping tabs on two male students who thankfully don't make my life too difficult. Melanie wanted her students to learn first-hand about "the border, immigration rights, environmental justice, sweatshops, etc."

Omeira is a senior whose parents came from Guanajuato, Mexico before she was born. Her father came to the US by crossing through a river. "In class, we learned about NAFTA (North American Free Trade Agreement) and the effects that it's had on Mexico....I just wanted to feel for myself what it is."

She got her wish. The day after arriving, we walk past a once-pristine river, on the outskirts of Tijuana. It is surrounded by makeshift shacks. The river is milky-grey, discolored by the pollution dumped from the 130 maquiladoras (export assembly plants, most of them sweatshops) up the hill. Littered with trash, the place has an overwhelming stench and, within a few minutes, my nose begins to burn. We stop beside the river, which is the community's main source of water. Jeremiah, a thin freshman in jeans and a black T-shirt, jokingly asks what would happen if he went for a swim. Our guide, a sharp and fiery woman from Tijuana, tells him that he would probably walk out with Hepatitis A, dysentery, and a number of other illnesses.

"Asthma, is un-ordinarily common here among the children," she says. "So are birth defects and malformations caused by poisoning from the lead dust, which blows down from the abandoned battery recycling plant up the hill."

With the ratification of NAFTA 11 years ago, US and other foreign companies began to open up maquiladoras at break-neck speeds, moving their factories south in search of cheap labor and lax safety and environmental laws. Hundreds of thousands of U.S. factory workers have lost their jobs, while 1.5 million Mexican farmers have been forced off their land, due to these unfair trade policies. Many of these small-scale farmers and their families traveled to the border to find work in the maquiladoras. Others have illegally entered the US.

Omeira doesn't think it's fair. "The people are poor," she says. "They are oppressed.... They don't have jobs and when they do, they don't get paid anything.... They work in maquiladoras. They don't have rights and they don't have any way to fight for their rights."

Benjamin Prado is the San Diego Area Coordinator of the American Friend's Service Committee. He is a friendly fellow, who has spent much of his life along the border. Gravel shuffles beneath our feet as we step from Prado's van into the hot sun and stare at the triple-walled fortification before us. Bustling Tijuana lays on one side; a US shopping mall on the other. Prado points to the wall.

"The panels that they used to build this border were military equipment that was used in the (first) Iraq War," he tells us as he explains Operation Gatekeeper, which was instituted the same year as NAFTA and re-enforced the border in the San Diego region and other urban zones. As a result, immigrants have been forced to cross the empty deserts and mountains of the Southwest. Since 1994, more than 3,100 migrants have died trying to reach the US. Nearly a thousand of the bodies are still waiting to be identified.

"The border is really sad," says Omeira. "Since I'm Mexican, I see the crosses on the border wall, and I think... these are my people... I want to help."

To the East, hundreds of miles away, vigilante militiamen prepare to stand guard in the thirsty deserts of Arizona, awaiting the refugees in this economic war, hoping to turn them away. It seems that many have forgotten the words engraved on the base of the Statue of Liberty: "Give me your tired, your poor, your huddled masses yearning to breathe free."

But these students haven't.

As we swelter in a long line of cars waiting to cross back into the United States, Rosanna, a freshman whose grandparents crossed the border from Mexico many years ago, says that the experience "motivates me to make a difference. I strongly invite other youth to come over here and see what's going on."

Mike Fox is a Bay Area writer and activist with the Green Festival and Global Exchange. He currently is works on the Global Citizen Center's campaign to stop the Central American Free Trade Agreement. You can visit www.globalexchange.org for more information.