September 11, 2001, began as an unusually pleasant fall day in Washington, DC, and along most of the East Coats — no clouds in the sky, a bright sun and good temperatures. I had just arrived at the U.S. State Department to take pictures of some foreign dignitaries visiting the Secretary of State.

Across the river at the Pentagon, American Airlines slammed into the Pentagon at 9:37 a.m., 34 minutes after the first plane hits the South Tower of the World Trade Center and almost an hour after the first plane hit the North Tower.

None of us in the room at the State Department knew of the events until my Blackberry notified me with a terse message: “Explosion. Pentagon. Get there.” It came from my assignment editor at AFP.

Others were getting similar messages and an official came in to tell us “there is a problem in New York and at the Pentagon.”

I sprinted to my parked Jeep Wrangler, with the top down, and dropped my cameras into the passenger seat, fire up the engine and headed for the 14th Street Bridge on Interstate 395, which crosses the Potomac and passes right by the Pentagon I could see a black column of smoke rising from the building, but I did not know, at that point, that a commercial airliner was involved or that it was part of a coordinate attack on America.

But 395 was blocked by police. Same for Memorial Bridge, so I headed down through Southeast DC to the bridge that passed over the Anacostia River into Maryland to get to Interstate 295, which would connect to 395 near Springfield, VA and, hopefully, north into the Nation’s Capital.

At the stoplight leading up to the bridge, right across from one of the entranced to the Navy Yard, I set in traffic and noticed it was locked down with Marines in full combat utilities and M-16s. One was a female Marine with her M-16 with a bayonet which was taller than her, so I picked up one of my Nikon D-1 digital cameras with a telephoto zoom on it and shot about a half-dozen photos of her and other Marines at the gate before the light changed, and I could drive over the ridge and North to I-95 to 395.

I found a parking space at a hotel across the Interstate from the Pentagon and, with my cameras and a bag, sprinted along Columbia Pike to a high area that looked over the Pentagon with a good view of the first and large gash in the building that houses our country’s military establishment.

The smoke was billowing out as I started shooting photos of the carnage. A fellow photographer asked: “What is that rancid smell?”

“A combination of fuel and burning flesh,” I said. I had last smelled it somewhere in another place and another time a long time before. It had hoped I would never smell it again. It was then I heard that a commercial jetliner had smashed into the Pentagon and two others had brought town the twin towers of the World Trade Center.

We shot photos continuously throughout the day, swapping out Compact Flash Cards, and I fortunately had several fresh battery packs. That batteries did not last long in early digital cameras.

I interviewed several who had witnessed the plane crashing into the building, including a cab driver whose taxi had been struck and disabled by a light pole the plane hit as it passed low over on Columbia Pike. My last battery died just before midnight, and I spent another hour interviewing some others who had witnessed the plane. My photos included much of the devastation and the faces of those who tried to save as many as they could. Several times during the day, a runner came by to retrieve my compact flash cards and bring fresh batteries.

When I got home — a condo on North Fairfax Drive in Arlington, not far from the Pentagon — a card from agent John Ryan of the Navy’s Criminal Investigative Service had been slid under the door.

“Please call me,” said the handwritten script on the back of the card said. At first, I thought it was a prank. John Ryan was the main character in Tom Clancy’s bestsellers.

After a short nap and shower, with by camera batteries recharging, I was sipping coffee shortly after the sun came up on Sept. 12 when I called the number on the card. “Ryan,” said the person who answered the phone. It wasn’t prank.

“Thank you for calling,” he said. “I need to follow up on some information we received. Were you in the vicinty of the Washington Navy Yard on 11 Sept.?”

“Yes,” I said.

“And what was your purpose there?”

“I was in my car waiting for the light to change.”

“Was that vehicle a black Jeep Wrangler with a Virginia license plate?”

“Yes.”

“Why were you taking photos of the Yard from your car?”

“That’s what I do,” I answered. “I’m a photojournalist.”

“For whom?”

“I’m a contractor for several news outlets. On Tuesday, I was on assignment for AFP.”

“Is there a quick way to confirm that?”

“The best way would be a copy of this morning’s Washington Post. There is a photo of a female Marine in full battle utilities and an M-16 standing post at the entrance on Page 6 of the paper.” I had found the photo when my paper arrived at my front door that morning.

I heard a rustle of paper on the phone before he came back on the line.

“So I see,” he said “Were you, by any chance at any other military installation on 11 Sept.?”

“Yes,” I answered. “The Pentagon. There are other photos in the paper and others that can confirm that.”

For the first time, he seemed to relax. He asked some other questions and asked me to confirm the last four digits of my Social Security number.

“That should take care of our interest in you,” he said.

Before he hung up, I had to ask.

“Do you get any questions about your name?”

“All the time,” he said. “I don’t go by ‘Jack’ but I’m called that now around our office. Clancy is very popular here.”

On Wednesday, I photographed the damage to the Pentagon and the faces of firemen and soldiers. Over the next weeks, I shot photos of those mourning in both Washington and New York.

A few days after 9/11, I dropped my wife off at her doctor in Falls Church, Va., which was just across the street from a movie theater that had a sign about the attack on its marquee. As I walked to the theater to shoot a photo or two of it, I hear a loud Harley-Davidson approaching and I had time to shoot on image of it passing with a tattered American flag flying from it. It remains my most treasured image of that terrible time, and appears in several hundred newspapers in America and around the world.

It was a grab shot, but for me, it showed a time when America united to respond to an attack on our way of life.