El Paso and its neighbor across the Rio Grande, Ciudad Juarez, are like reverse photographic images of each other.

One is a model of civic order, the other an urban war zone just a few hundred yards away across the Mexican border.

In Juarez, people have been lined up against a wall and shot to death. Victims' limbs have been cut off. Bodies have been left to rot in the torrid streets or buried in shallow desert graves. Gun battles break out in broad daylight, with children and other innocents caught in the crossfire. Residents are afraid to leave their homes.

In El Paso, Friday nights in the fall are dedicated to high school football, and a Christmas tree lighting and holiday parade downtown draw thousands on a chilly December night.

A grisly war involving Mexico's ruthless drug cartels has killed as many as 4,000 of Juarez's nearly 1.5 million people over the past two years, making it one of the most dangerous cities in the world.

El Paso, with a population of more than 600,000, has had fewer than 30 murders in that same period and was recently named America's second-safest city of its size, behind Honolulu, by Congressional Quarterly.

How has El Paso managed to escape the mayhem going on across the border? The chief explanation, according to experts on the drug trade, is that the traffickers have kept their base of operations on the Mexican side and do very little business in El Paso itself.

Many people in El Paso are grateful and brag about the low crime rate in this corner of far West Texas.

"We've had this designation ... since the beginning of the new millennium," City Councilman Steve Ortega said. "It's been a long-standing sense of pride that now is even more remarkable, given what's taken place in Ciudad Juarez."

'We are all scared'

While El Paso residents enjoy the Friday night lights and holiday outings, their Mexican neighbors live under siege.

They have to make their way past checkpoints manned by some of the more than 7,000 army troops stationed in Juarez. They worry about ending up in the wrong cafe at the wrong time, and don't look at the people in the car next to them at a stoplight for fear the occupants will open fire.

Slideshow: Mexico under siege "Here in Juarez, I'm in my house and hear shots every day and I hear ambulances and I wonder who just died," said Humberto Rico, who works at the Autonomous University of Ciudad Juarez and marched with thousands of others in a recent protest against the bloodshed. "This is every day. We are all scared. We don't leave the house — not me or my children — not to eat or to go to the movies because there are shots all the time."

For years, some law enforcement officials, politicians and supporters of tightened borders have warned of the potential for a catastrophic spillover of bloodshed similar to what happened in Miami when it became a center of the cocaine trade in the 1970s and '80s.

But nothing even close to that has happened.

One explanation given: While violence tends to follow drugs and money, in El Paso the drugs and money are mostly just passing through, said David Cuthbertson, the FBI agent in charge in El Paso. Cuthbertson said the marijuana and cocaine smuggled across the border are bound for bigger cities, including Phoenix and Los Angeles.

El Paso has also been spared drug violence because the Mexican cartels have managed their operations from Mexico, with its lower cost of living and "easier-to-buy-off police," said Peter Moskos, a professor at the John Jay College of Criminal Justice in New York.

Howard Campbell, a sociologist at the University of Texas-El Paso and expert on the violence in Juarez, said the Mexican cartels learned a lesson from the Colombian druglords who set up operations in Miami — that causing mayhem on the U.S. side can bring a crackdown from law enforcement.

"In a way you could say Miami was kind of an experiment and Mexican cartel people wouldn't want that to happen again," Campbell said.

El Paso is not completely immune.

"There's not one person that I know that hasn't been affected either directly or indirectly, from the person who has a loved one over there that they can no longer see to those El Pasoans that would casually shop or dine in Juarez," Ortega said.

Some El Paso residents have to make the nerve-racking trip into the war zone daily.

Ernesto Arzaga, who lives in El Paso with his wife and two daughters, crosses the border every day to run a hair salon and restaurant. His shop has been robbed twice, and he said he gets routine demands for protection money.

"When you cross the bridge, you don't feel safety, you don't feel security," Arzaga said. "You don't trust either the soldiers or the policemen. You don't trust anyone."

His wife calls him routinely during the day, and if she can't reach him, she often sends a friend from Juarez to look for him. And as soon as Arzaga crosses back into Texas, he lets her know.

"She's fine when I cross the bridge," he said.