If this feature story, based on the book "Unembedded," offers an explanation of what it means to work as a journalist outside the U.S. perimeter, it is also an involuntary exorcism of intense memories.

There have been worse battles in Iraq since the late summer of 2004, but that doesn't matter. One death is still a death. It is the end of a universe. The photographs in this feature story, many of which were taken in Najaf during the siege that August, are the bright traces of the moments we witnessed there, and it is impossible for me to see them now without hearing the detonations, the entreaties, and the terrible silence of that time.

During the siege of Najaf, a holy city to tens of millions of Shiite Muslims, the five of us - four photojournalists and I - were drawn together, pulled into a fierce orbit around the gold tomb where the saint Imam Ali lies buried.

On Aug. 17, 2004, close to the height of the U.S.-led siege of Najaf, Thorne Anderson, Yassir Jarallah and I crossed the U.S. cordon and the Mahdi Army lines on foot, thinking that if we could get to the old city, we would be able to understand what was happening at the center of the Mahdi movement. Very little information was coming from the old city inside the cordon because few reporters had made it through the blockade. Most had been turned back by gunfire or had been rousted from their hotel rooms by Iraqi police. For a period of a few days, journalists were threatened with arrest if they remained within Najaf city limits. We wanted to find our way through the cordon and break the news blockade.

On the day we crossed the cordon, Kael Alford was taking photographs of a Najafi family trapped by the fighting near the desolate zone that characterized the front lines. Rita Leistner, who arrived in Najaf the following day, was in Baghdad, tirelessly negotiating the release of our colleague Micah Garen, a Mahdi Army hostage in Nasiriyah. Ghaith Abdul-Ahad, whose columns for the Guardian are some of the best reporting to come out of the war, arrived in the shrine that evening and captured a doomed peace delegation as it met with Mahdi Army officials. I remember seeing his blue flak jacket as he followed the dignitary Hussein al-Sadr though a chanting mob of fighters.

As Thorne and I crossed the U.S. cordon with our hands in the air, we found ourselves in a landscape of burned buildings and smoldering cars. We continued over broken glass and melted plastic through a ruined market where we finally came across the first Mahdi Army position. We waved to a group of heavily armed men wearing black shirts, crouching in an alley, and when the fighters saw us, they did not arrest us. Instead, the commander sent an unarmed messenger to show us the path through the fighting to the old city. We walked to an open space where a wide street divided the old city from its newer sections. When we reached the middle of the street, where it was impossible to turn back, a sniper fired on us, and there was a cracking sound and dust in the air from the rounds hitting the concrete pillar above our heads. Thorne lay down in the road, finding shelter under a low concrete barrier. I ran behind a column.

When the shooting was over, we walked slowly to the shrine in the old city, past dozens of fighters in black, leaning against the walls with their weapons. It was a moment of relief, of somber triumph. Other photographers and journalists who have risked everything to cover the war from the other side know this feeling well because they have made this crossing or one just like it many times. Fighters on the other side of the street took us in, and there was an innocent, human quality in this moment that I cannot describe even a year later. It would have been easy for them to kill two American journalists, accuse them of being spies, but they did not. Perhaps that is all that needs to be said.

In the old city where most of the fighting took place, the sound of the great machinery of killing focused on a small space came through the air in shattering waves. A few dozen yards away from the great shrine of Imam Ali,

Hellfire missiles fell from Apache helicopters and smashed buildings into their basements, rocket-propelled grenades flew down Prophet Street, machine guns chattered in bursts. We watched young men rushing through the gates of the shrine, down Prophet Street toward death. In this way we learned that all of the weapons have their own distinct voices. Soon it was easy to imagine the machinery of war as demons, and the siege of Najaf as a war between heaven and hell. This was how the Mahdi fighters saw it. For them, it was a war of faith.

We entered the southern gates of the shrine and saw the tomb of Ali in the center of an expanse of polished white marble. The reflection of the sun off the gold minarets made them look like vessels being fired in a kiln. Wounded fighters were being carried through the gates to a makeshift infirmary in a small alcove, as the Mahdi lines collapsed around the shrine. Older men who tended the mosque wiped up the trails of blood from the wounded. The young men in black T-shirts and green headbands ran down Prophet Street toward the American lines and came back on wheeled carts, their bodies torn apart. After they died, comrades of the dead fighters wrapped them in white and carried them in a final circuit around Ali's gold tomb, shouting, "There is no god but God."

While I filed reports for the radio and gave interviews over the satellite phone, Thorne took hundreds of pictures of the fighters in the shrine and near the front lines, documenting what I was unable to describe in words. He showed them eating meals, praying and fighting, the whole extent of their lives under fire. In his photographs you can see the connection he had made with the young Mahdi volunteers and the trust he had gained.

A few blocks to the north of where we slept, hundreds of Mahdi Army soldiers were hiding in a vast graveyard, a necropolis far larger than Najaf itself, with more than a million people buried in the sacred earth. Fighters huddled down in the dust of the tombs, firing at U.S. positions. We heard the sound of the missiles that destroyed them. The other men who took their place picked up the weapons of the killed and fought until they also died. The war and the routine that surrounded it functioned with mechanical regularity. And because machines are predictable, you always knew what would happen before it happened.

Three days later, on Aug. 19, after learning that we couldn't safely leave the old city the way we had come in, Kael Alford and Rita Leistner brokered a cease-fire between the U.S. military and the Mahdi Army. It was the first step in a plan to evacuate us from the shrine. Riding in the first car of a convoy of journalists, Kael and Rita made their way into the old city, past the nervous fighters who fired warning shots to stop them. While some of the journalists in the convoy decided to turn back, Kael and Rita continued through the ruined city.

At four o'clock, dozens of journalists entered the shrine to bring us out, get quick interviews, take photographs of the Mahdi volunteers who were shouting and chanting Muqtada al-Sadr's name. I had first heard that they were coming when a young fighter ran up to me and said, "The journalists are coming."

"Which journalists?"

"All of them!" the boy said. An hour later, when Rita and Kael arrived, it seemed like a species of miracle. After we returned to Baghdad, we were shocked by some of the reactions people had to our work during the siege.

One U.S. officer who was angry that we covered the other side of the conflict in Najaf accused us in a New York Times editorial of putting American soldiers at risk. I am not sure what he meant, and it is certainly not true. Another man, in an Internet posting, threatened Thorne's life because of the photographs he took behind the Mahdi lines. This is a short catalog of incidents, but all of us have been escorted out of places, threatened with the loss of press credentials or with arrest. There are always consequences when stories run, but I was surprised by the bitterness and vehemence of the accusations, the absurd insinuations of treason.

We crossed the lines because we believe it is more important to humanize a conflict than it is to trade in rhetorical truths, or to reinforce easy notions of enemy and friend, which are mere propaganda. Instead, we wanted to document honestly what we witnessed in the war because this is the sole duty of journalists, regardless of their nationality and religion. We were able to do this precisely because we did not carry weapons or claim allegiance to one of the warring parties.

If our journeys behind the lines were acts of faith, then they were also proof that often when one man is confronted with the humanity of another, he will not raise his rifle and pull the trigger. This is not disloyalty to one's country. It is the thing that brings an end to war.

Now, here are your witnesses.