Border Patrol agent Richard Gonzales pushes a button in the shiny white Chevy Tahoe he’s driving. In response, a gate rolls open to allow entry to the no-man’s-land between the secondary fence and the old primary fence. The gate is in Otay Mesa, maybe a mile west of the port of entry.

Gonzales turns west onto a two-lane graded dirt road between the fences. The view here is striking. On the right towers a 15-foot fence made of a perforated metal similar to a front-door security screen. It’s the kind of structure that could only be built in a wealthy country. It glimmers with fresh gray paint and is topped with coils of nasty razor wire. The fence stretches 13 miles from east of the Otay Mesa port of entry to the ocean. The final section, in Border Field State Park, should be completed in May.

By contrast, on the left, the northwest corner of impoverished Latin America piles up against a ten-foot fence made of rusty corrugated-metal panels. Houses constructed of plywood, old garage doors, and bare concrete blocks cling to canyon sides, buttressed by retaining walls made from old tires stacked and filled with soil. Each 15- or 20-foot section of the primary fence bears a spray-painted number. The numbers get lower as we go west. The fence panels are Vietnam-era landing mats — they were used to make instant runways. “That was the material we had on hand when we built this fence in the early ’90s,” says Gonzales, who has spent his entire 22-year Border Patrol career in San Diego. “Before that, it was chain-link, some barbed wire.”

The old fence, Gonzales says, didn’t stop many illegal immigrants. “In fact, when I started in 1987, we didn’t even patrol this area. We waited for them about a mile north of here.”

Outnumbered Border Patrol agents in those days essentially conceded this rugged country of mesas and barrancas to the border crossers, their guides, and groups of roaming banditos who preyed upon the immigrants. “They knew these people were carrying their life savings with them. So they robbed the men, raped the women, and there wasn’t much we could do about it. It was just too dangerous for an agent to be out here alone.”

Every 300 feet or so along the road between the fences stands a light pole. Some of the poles have one-by-two-foot sheet metal signs hanging from them, emblazoned with names such as Soccer Field and Washer Woman’s. “Those are the names we called the different areas back in those days. Soccer Field was a flat area where men would gather and play soccer before they crossed. Washer Woman’s is where women would gather and make money washing clothes for the men.”

But nobody plays soccer on Soccer Field anymore, and there are no women washing clothes at Washer Woman’s. Operation Gatekeeper, the boost in manpower and border fencing launched in 1994, has put a stop to that. Not that nobody tries to cross in these areas. Jumping the landing-mat primary fence is not a difficult feat. But the 15-foot secondary fence topped with cruel razor wire is a much more formidable obstacle. “The top of the fence used to lean [southward]. We thought that would be enough. But they were making long ladders out of wood and going right over. So we added the razor wire. A few have tried going over the razor wire by putting blankets on top, but it’s dangerous and time-consuming. So mostly what we see now is people cutting through the fence with blowtorches.”

As the Tahoe slowly bounces down the rugged dirt road, Gonzales points out areas where the gray fence has been repaired. Dark gray lines indicate where the metal has been cut, then welded. “We have welders out here every day fixing the fence,” says Gonzales. As if on cue, a pickup truck festooned with toolboxes and welding equipment comes up the road from the west.

But people taking this route are not often successful, Gonzales says. Pole-mounted lights and cameras allow remote monitoring of every inch of the fence, and cutting through takes a little time. Even if they make it through, Gonzales says, they usually don’t make it far.

A hundred yards east of the San Ysidro port of entry, train tracks cross the border. The trains “get x-rayed when they come north, right in there.” Gonzales points to a small rail yard just north of the secondary fence. The numbers on the primary-fence panels go down to zero at the border crossing. They start going up again on the other side as the Tahoe rumbles down the narrow dirt road between the fences, which now stand on the crest of the Tijuana River levee. A shopping center lies over the fence to the north. After a couple of hundred yards, the fence stops. Here the Tijuana River and the border cross each other, an eternal monument to borders drawn without regard to natural landmarks. There’s no fence across the channel. Today, barely a trickle runs down the middle, but during times of heavy rain, a wall of water roars down the concrete channel through Tijuana, bearing with it raw sewage and all manner of urban runoff, before spreading out over the floodplain and meandering through a maze of natural channels five miles to the Pacific. On this early April day, the floodplain is a lake of purple, white, and yellow wildflowers. The flowers have grown up in the moist soil as the floodwaters of winter’s rain receded. The colorful carpet hides the garbage that has washed down the river, though not completely. Here and there, an old tire, a sofa, a car door stick up through the mud. Plastic grocery bags litter the low branches of surrounding eucalyptus trees.

Gonzales steers the Tahoe onto Camino de la Plaza, then crosses the floodplain via the Dairy Mart Road bridge. On the south side of the river, he turns onto Monument Road. Ahead lies the field headquarters of Kiewit Corporation, the firm building the new all-weather road west to Border Field State Park. Half a dozen or so yellow-and-black Kiewit vehicles are parked around the headquarters. A wry smile flickers on Gonzales’s face as he drives by. “Recently, we apprehended a juvenile female driving a truck painted to look like one of those Kiewit trucks. Their foreman happened to spot the truck, realized it wasn’t theirs, and called us.”

Past the Kiewit yard, Monument Road meets the secondary border fence. Gonzales pushes a button, the gate slides open, and the Tahoe is back in no-man’s-land, heading west. Soon the graded dirt road becomes smooth blacktop, so new the blacktop is unfaded. The road climbs, paralleling the grade on Avenida Internacional, which hugs the south side of the primary fence. At the crest of the hill, the road levels out and stretches across the top of a newly completed earthen berm. The berm stands about 150 feet tall and stretches four times that from end to end. It was constructed with 1.3 million cubic yards of earth cut from the surrounding hills. It fills in Smuggler’s Gulch, a deep wash that extends north from Mexico and ends at the Tijuana River floodplain. Until Operation Gatekeeper, the gulch, as its name implies, was a hangout for smugglers of drugs, immigrants, and illegal alcohol, during Prohibition. As he steers the Tahoe down a road that descends the south face of the berm, Gonzales recalls, “When I started, this area was full of immigrants and smugglers staging here, waiting to cross. There were a lot of old burned-out cars down there because they used this canyon for drive-overs.”

A drive-over is when illegal immigrants attempt to beat la migra by piling into a vehicle, opening a hole in the fence, and driving through. But the days of driving through Smuggler’s Gulch are definitely over. The berm, bristling with light standards, crowned with the secondary fence, has put a stop to that. At the bottom of the hill, a shorter berm, across which runs the primary fence, funnels water into twin concrete culverts, each ten by ten feet. Gates made of six-inch-thick steel bars block the culverts to foot traffic. Culverts of similar dimensions run under the main berm and spill out in the river valley. Today, there’s no water running under the berms. “But a lot of water comes out here when it rains,” Gonzales says. “So we open these gates to let it through, otherwise there’d be a lake in Mexico.”

Some in Mexico are concerned that not enough care was taken to ensure proper drainage of the Valle Montezuma, as Smuggler’s Gulch is known south of the fence. Dr. Juan Manuel Rodríguez Esteves, director of the Department of Urban Studies and the Environment at Tijuana’s Colegio de la Frontera Norte, is concerned that the berm will “clog the arroyo. The problem is that on the Mexican side, there is a deficit in public services, for example, garbage collection. This has been going on for many years within the history of the city. In Tijuana, it rains about 240 millimeters [about nine and a half inches]. But in years of El Niño, like in 1993 and 1998, it doubles. And when the intense rain comes — and they are intense rains — it brings all the trash, it brings abandoned cars to the lower part of the canyon, and what is going to be happening is the berm is going to become a dam.”

Told of Rodríguez’s concerns, Gonzales shrugs and says, “I don’t know why he’s worried. The Mexicans built their own berm across the gulch a long time ago.” He points to the berm about 500 yards south of the border. The highway connecting Tijuana Centro and Playas de Tijuana runs across the top. “If there were going to be a problem, it would have happened over there.”

Before the berm was built, Border Patrol agents had to traverse the canyon via steep dirt switchbacks on the canyon sides. The roads were narrow, bumpy, and subject to washouts in bad weather. Now, Gonzales’s Tahoe zips across Smuggler’s Gulch in a couple of minutes. West of the gulch, the road descends gradually and crosses over a much shallower gulch running north from Playas. “We discovered Kumeyaay artifacts here, so we had to build up this area so as not to disturb them.”

Here there are three fences, the landing-mat primary, the razor-wire-topped secondary, then a chain-link tertiary fence, maybe 30 feet north of the secondary. “We recently bought this area from the County,” Gonzales says. “The third fence is basically to delineate the boundary between federal and county land.”

The all-weather road hasn’t been completed all the way to the ocean yet, so Gonzales turns off onto a dirt road still flooded from winter rains. He drives 100 yards through water halfway up the tires; then the road climbs to the little mesa on which sits Border Field State Park. The only thing that marks this as a park is a handful of concrete picnic tables surrounded by thigh-high weeds. The Playas bullfighting ring and lighthouse loom across the fence. Until recently, people were able to come to this park and talk to people on the south side. Newspaper stories reported that families would hold binational picnics here, passing food through the fence and playing volleyball over it. But the Border Patrol doesn’t allow that anymore. “It was reported as if we were trying to break families apart,” Gonzales says, “but it was a smuggling nightmare. All sorts of things were being passed through the fence. People were using their crossing cards, then passing them through the fence here to someone else. Drugs were being passed through, even babies were being passed through. The volleyballs you heard about — they were filled with marijuana.”