BAGHDAD — Ahmed Hassan was waiting for his ride home, and he was trying not to look like himself.
No rings that might let someone know that he's a Shiite Muslim. No books that might reveal that he's a student at Baghdad University's Medical College. Standing next to the bridge that connects east and west Baghdad, he was hoping to be invisible. That, he hoped, would get him home alive.
With the other medical students, he'd studied the maps, compared stories, checked violence reports and come up with that day's route home. "All we chat about at school these days is how to get home," Hassan said.
It's the latest daily ritual in an ever-shifting Baghdad. Even as violence drops in Iraq's capital, residents have become obsessed with how to move around the city safely.
Baghdad has become a crazy-quilt patchwork of sectarian fiefdoms, each controlled by a different armed group. Some are ruled by Sunni Muslim gunmen, others by Shiite militias, still others by the Iraqi army and yet others by U.S.-backed tribal groups.
Their borders might be visible: concrete barriers swung into place by huge cranes or barbed wire coiled across a street. But many simply end and begin, with nothing to alert a hapless traveler.
Stumbling into the wrong one can mean death at the hands of an armed member of a different sect. A street that's safe for Sunnis often isn't safe for Shiites. A block that's safe for Shiites may be dangerous for Sunnis. Fear is the only constant.
Army Gen. David Petraeus, the top U.S. military commander in Iraq, describes the zones as "micro fault lines." Iraqis see them as deadly obstacles to ordinary life. Many never leave their blocks.
Hassan, 23, dreams of the day when he'll be able to travel into Sunni neighborhoods without fear, as he remembers doing not so long ago. "I went to a school in a Sunni area," he said. "I have Sunni friends, and I want to see them."
But that's for another time. Now, each day brings worries about whether a safe route has become dangerous. Unheralded battles across the city can change the fault lines overnight.
Those who must venture out almost never take direct routes.
Shiite workers at the power station in the Dora neighborhood — a stronghold for Sunni insurgents allied with al Qaida in Iraq — take a boat across the Tigris River to get to work rather than risk navigating the neighborhood.
Residents of Sadr City in the capital's northeast who want to visit the Shiite shrine in Kadamiyah — just across the Tigris to the west — loop far to the south and work their way back north. The direct route is seven miles and takes 20 minutes; the new one is 15 miles and takes an hour.
At Medical City, Hassan wore khaki pants and a beige plaid shirt. His black hair was neatly combed. He was quiet, but the streets were filled with noise and color. Women were wearing bright-colored hijabs, or veils, and everyone was headed somewhere.
Hassan usually rides a minibus or gets a ride from his cousin. Today he was riding with a reporter, who'd asked to see how he gets home.
The Medical City area is a good example of how control can shift. A few months ago, the Mahdi Army militia of anti-American Shiite cleric Muqtada al Sadr controlled the area. The nearby Ministry of Health was headed by a Sadr supporter, and he also governed everything nearby. Few men came here, afraid of being kidnapped or worse. Women in black abayas, the full-length covering of the conservative faithful, hustled to and from the morgue, searching for their missing men.
Nearby Haifa Street was a war zone controlled by Sunni gunmen. No Shiite could venture there.
Then, last spring, things changed. The Sadrists dropped out of the government and the Mahdi Army left the Medical City area. Men returned, and it became possible for Sunnis to visit the morgue again. The posters of Sadr disappeared.
Haifa Street also changed. U.S. and Iraqi government troops, backed by American helicopter gunships, forced out the Sunni insurgents. A few weeks later, Hassan and his friends decided that Haifa Street was safe enough to travel on, as long as they didn't venture down any side streets. It cut his commute by 10 minutes, he said.
"The most dangerous road in Baghdad, but not nowadays," Hassan said as his car passed the first checkpoint in front of Haifa Street. "Now it is normal."
Hassan directed the driver to take a left on Haifa Street.
Most of Hassan's route took him through Sunni areas. As he passed through them, he stuck to main roads.
"The main roads are mixed," he explained, meaning that both sects use them and the checkpoints are certain to be manned by legitimate members of Iraq's security forces.
Every few blocks, he saw a reminder of a city thrown into chaos and, in some cases, redeemed — at least for now. Fifteen minutes from home, he passed Nisour Square, infamous for the deaths of at least 17 Iraqis whom private American security guards shot in September.
"Blackwater," he said as the car raced by.
Moments later, he pointed out the window to a street block by low concrete barriers, painted blue and yellow.
"Shiites can't go here," he said.
A few blocks later, he pointed again. Another blocked road, this one manned by gunmen.
"The Sunnis can't go there," he said.
As the car turned onto the main road into Yarmouk, a Sunni enclave, Hassan fell silent. A few blocks away, he'd been almost kidnapped when he and some friends took an unplanned route down a side road. Sunni gunmen had set up a fake checkpoint. The gunmen seized two of his friends and threw them into the trunk of a car.
Hassan was next. A passing U.S. convoy saw the gunmen and stopped.
Hassan explained what had happened and the soldiers detained the gunmen and released Hassan and his friends.
That's when Hassan stopped seeing Baghdad as his home and began to see it as a maze to be navigated.
"After that, I started changing my routes," he said. "The Sunnis take the Sunni roads and the Shiites take the Shiite roads."
He volunteered a defense for why he still travels this way: "There is no other way for me to go."
At the Bayaa bridge, the gateway to Baghdad's Shiite neighborhoods, Hassan grew calmer. He was almost home.
He waved at the guards at the checkpoints, many of them employed by the same Mahdi Army that once controlled Medical City. He said he felt safer, even as he passed the charred spot in the street where a car bomb had exploded Sept. 15, killing 10 people and injuring another 15 who were standing outside a bakery.
But he wasn't home yet.
Hassan had to travel south to enter Amil, his neighborhood, skirting the Sunni snipers who'd taken positions at the northern end of April 7 Street. He pointed to the windows where he said the snipers waited, and, a few streets later, to the home of someone who he said was their most recent victim.
He was nearly home, as he ordered a left into a Shiite area. Still, there was one more detour — a sharp left off the main thoroughfare — before he pulled up in front of his house. He was once again at ease.
Soon, however, he'd begin conferring with neighbors and calling fellow students to figure out how to get back to school the next day. Baghdad would have changed again.