One mile deep into the drafty tunnel under this hilly frontier city, a flashlight beam cuts through the pitch-black darkness and illuminates a yellow line painted on the concrete wall: the U.S.-Mexico border.
Just beyond the boundary a graffiti-message believed to have been scrawled by U.S. law enforcement warns intruders: “USA Tunnel Rats. Este lugar es de nosotros”—This place is ours.
Inside the largest known tunnels on the border—two passages that make up an enormous drainage system linking Nogales, Mexico, with Nogales, Ariz.—migrants stumble blindly through toxic puddles and duck low-flying bats. Methamphetamine-addicted assailants lurk. And young men working as drug mules lug burlap sacks filled with contraband.
There are shootouts and rapes. Rising floodwaters sweep people to their deaths. U.S. Border Patrol agents pursue smugglers in frenzied chases, insults and threats echoing as they go. And tangles of rebar metal—points sharpened by smugglers—gouge people who get too close to some walls.
As the United States prepares to fence much of the border above ground, the situation below ground could grow increasingly chaotic. Authorities have discovered dozens of illegal tunnels in recent years, including a nearly half-mile passage connecting Tijuana with San Diego.
Illegal immigrants have breached drainage systems all the way along the border, from El Paso to San Diego. Most of them are of the claustrophobic crawl-through variety that prevents large-scale incursions.
The Nogales tunnels, by comparison, are superhighways.
Once open waterways, today they stretch for miles under the traffic-clogged downtown streets of both cities, zigzagging roughly parallel to each other.
Above ground, fences, sensors and stadium lighting clearly separate the two cities. Underground, they remain linked of necessity by the system built decades ago to channel monsoon rains.
In recent years, the U.S. Border Patrol has had some success stemming the underground flow of illegal immigrants and drugs by installing heavy steel doors, surveillance cameras and sensors. But when heavy monsoon rains this summer triggered floodwaters that tore down the gates, smugglers ripped down the cameras and shattered the lights and siren used to discourage incursions—and the chaotic human flow resumed.
From July through October, agents apprehended 1,704 illegal immigrants in the tunnels, a nearly five-fold increase from the previous six months. Agents seized more than a ton of marijuana from tunnel arrests during the same period. In July, bandits raped two women from Oaxaca, Mexico, in the tunnels on the Mexican side.
Patrolling the tunnels is a tactical nightmare for law enforcement on both sides of the border, mainly U.S. Border Patrol agents and Grupo Beta, Mexico’s migrant safety force.
U.S. agents often can’t go into the Morley Tunnel because overpowering ammonia and chlorine smells leave them nauseated and dizzy. On the Mexican side, some stretches of the tunnel are so low that Grupo Beta agents ride their all-terrain vehicles lying on their stomachs.
Teams of U.S. agents enter the Grand Tunnel daily, sometimes toting M-4 assault rifles. But their high-tech night vision goggles are rendered almost useless in the tunnel’s black hole-like reaches.
A distant flicker of flashlights—sometimes half a mile away—usually signals an approaching group. They could be drug traffickers or bandits or illegal immigrants. Some have walked one mile already after descending from Avenida Reforma in Nogales, Mexico, taking advantage of the cracked grate in front of Elvira’s Bar.
The groups cross the yellow line in complete silence—the only sounds the distant hum of traffic, the chirping of crickets, the scurrying of rats. Sometimes the tunnel itself seems to be alive, producing from the humming and air flows a pulsing, low groan.
The darkness is so thick that migrants sometimes cross within an arm’s length of U.S. agents without noticing. That’s the agents’ preferred tactic: lying in wait, pressed against the walls, letting groups pass before pouncing and cutting off any escape back to Mexico.
Some illegal immigrants are so startled that they run smack into the walls, agents say. During one sweep last December, when smugglers heard them coming, agents yelled out: “Somos migra!”—Border Patrol. They ordered the group to stop.
“Migra go home!” came the shouted reply as the people ran back into Mexico.
If the migrants manage to evade agents in the tunnels, another huge challenge remains: getting out. People pop up from manholes into the middle of busy streets, sometimes stopping traffic.
Curb storm drains are often too small, so smugglers use hydraulic jacks to pry them open so people can squeeze through.
Some grates have been opened so often that Nogales city workers have placed huge boulders and concrete blocks on top of them. At a park, one manhole was covered with a steel plate and a bench to prevent breaches. One curb storm drain downtown was pried open so often that the sidewalk buckled, leaving a telephone pole listing over parked cars near a furniture store.
Now many migrants walk a mile past where the border is marked underground to reach the open end of the drainage tunnels. Outside again, they climb an embankment to waiting cars.
Border Patrol agents hope to regain control of the tunnels after the rains stop and they are able to repair the gates and cameras at the border. But Mexican authorities doubt that it will make much of a long-term difference.