WASHINGTON - A year ago, as the Pentagon burned, soldiers in full body armor and carrying automatic weapons patrolled an expanded perimeter around the White House.
Camouflaged Humvees were parked on downtown street corners, and F-16s circled menacingly overhead.
Now, the soldiers, Humvees and jet fighters are gone, and life in the nation's capital - the other ground zero - appears back to normal.
But things might never be the same.
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Staff members on Capitol Hill are learning how to don emergency breathing devices known as Quick2000 Escape Hoods. Radiation detectors have been quietly installed near the White House. Fifty tons of emergency medical supplies have been stockpiled in a secret suburban warehouse. And the sound of a siren or a low-passing jet still makes people edgy.
At the Pentagon, where 189 people died when American Airlines Flight 77 slammed into the west-southwest side of the building at 500 mph, the limestone façade has been replaced, and people began moving back into once-devastated offices in mid-August. Almost 1,000 construction workers have labored round the clock on the $500 million project.
"I come to work here every day," said Lt. Col. Ryan Yantis, who was in the Pentagon the day of the attack. "It's not a flashback, it's a daily reminder. It's always present."
Yantis, a former cavalryman, served two tours of duty at Fort Lewis in the early 1990s and now works in the Army's press office. He vividly remembers Sept. 11 - checking his smoke-filled office not far from the crash site to make sure everyone had escaped, and the "surreal scene" when he got outside, helping to remove the injured and carrying stretchers.
To many, including Yantis, the Pentagon might be a legitimate military target. But using hijacked civilian planes as weapons was a "cowardly act," he said.
As elsewhere, security has been significantly tightened around the Pentagon, with military police highly visible and security vehicles with flashing lights blocking access roads.
"It's not mindless vengeance I want," Yantis said. "I have two little girls, and I don't want them growing up in fear. I'm not after revenge. But we need to be resolved in fighting this, resolved in making this a better world for our kids."
A month after the Pentagon attack, anthrax was found in the office of Senate Majority Leader Tom Daschle, and a new fear swept Capitol Hill and the rest of Washington.
Mail delivered to congressional offices is now irradiated, streets have been blocked off with concrete Jersey barriers and 25,000 breathing hoods have been bought to protect lawmakers, staff and visitors against chemical and biological attacks.
"I'm not more anxious, I am just more aware," said Jennifer Crider, press secretary for Sen. Maria Cantwell (D-Wash.), whose offices were evacuated for 95 days after anthrax was found in the Hart Senate Office Building. Crider was among those who took the antibiotic Cipro for weeks.
"I am arguably in the safest place in the country," she said. "But when we hear fire alarms, we now bolt out of there."
Security officials and police refuse to talk about new precautions, but truck traffic recently was rerouted around the White House, 14 evacuation corridors leading out of Washington have been identified and surveillance at national monuments and Smithsonian museums has been increased.
A shadow federal government also has been set up at bunker locations in Pennsylvania and Virginia, where 75 to 100 senior government employees are assigned in rotating shifts. Their job would be to keep the country running if Washington were wiped out.
Tourists continue to roam the city, though the Smithsonian said 1 million fewer visitors toured its museums in July compared with a year ago. The 20 percent drop in July, though, was nothing like the near 50 percent falloff in the months after the attack.
For those who live and work in Washington, it's been a matter of learning to cope.
"People were pretty hysterical there for awhile," said Alan Etter, a spokesman for the D.C. Fire Department. In the weeks after Sept. 11 and the discovery of anthrax, the fire department was receiving 50 hazardous materials calls a day, Etter said. It's now back to pre-Sept. 11 levels of four or five calls a week.
Recent studies show slightly elevated levels of post-traumatic stress disorder in Washington; much of the rest of the country shows slightly higher levels as well. In New York, 11 percent of the population show symptoms, three to four times the national average.
"D.C. is dealing with this really well," said Dan Lieberman, director of Clinical Services in the Department of Psychiatry at the George Washington University Hospital.
Even so, memories of Sept. 11 persist.
"I expect another attack, and obviously D.C. is a likely target," said Jim Morris, a Maryland resident who works for Treasury.
"In the back of my mind, if anything happens, I work only a block and a half from the White House."
Les Blumenthal: 1-202-383-0008