AS the world remembers all those who died in the terrorist attacks in America a year ago today, this report from USA Today highlights some of the heroism that emerged from the terror at the World Trade Centre towers

By Martha T Moore and Dennis Cauchon, USA Today HERE

IN the crowded elevator lobby on the 78th floor of the World Trade Centre's south tower, Donna Spera cried on the shoulder of her friend Casey Parbhu.

Just after the explosion in the north tower at 8.46am on September 11, she had run to the window and seen smoke and flames engulf the floor where her friend Paul Innella worked.

She had dialed Paulie's number. No answer. She had talked to her husband, Ted. She had called 911.

Crying, she walked down 22 flights to the 78th floor elevator lobby, Casey's comforting arm around her all the way.

They huddled there with four other friends, in a crowd of worried, uncertain, people who were waiting to board elevators that could whisk them to the ground in a minute.

Spera didn't know what had happened in the north tower. She had no way of knowing that a second jet was roaring toward her.

In the terrorist attacks on the World Trade Centre, the 78th floor elevator lobby was where life and death intersected most violently.

At 9.03am, United Airlines Flight 175 cut like a scythe through the packed elevator lobby. Death's scalpel sliced between people standing inches apart, killing one while sparing another.

Based on information from survivors, USA Today estimates that 200 people were in the 2,600-square-foot lobby when the jet hit. It was the deadliest place in the south tower.

About one third of the 611 people who perished in the building died there.

Just 12 people who were in the elevator lobby when the second jet hit escaped before the south tower collapsed 56 minutes later.

Nine were at the north end of the lobby, farthest from the jet's impact.

Three were in alcoves off the main lobby, in local elevators that went to higher floors.

Everyone else on the 78th floor died, even people who had guided survivors to escape routes.

USA Today talked to seven survivors of the 78th floor to learn the story of what happened. The newspaper also interviewed others who passed through the elevator lobby.

In the sixteen-and-a-half minutes between the first strike on the World Trade Centre and the second, the dozen who survived the 78th floor never knew just what was happening or the danger they were in.

They didn't know that every action they took influenced whether they lived or died that day.

Judy Wein, aged 45, and Gigi Singer, colleagues from Aon insurance's risk analysis group on the 103rd floor, had seen a fireball shoot out of the north tower and blow past their windows. The flames were so hot, Wein felt as if she was standing in front of an open oven.

They ran to the emergency stairwell. In 10 minutes, they made it down to the 78th floor. There, Wein decided to stop off in what was known as the skylobby -- a transfer point between local elevators to the higher floors and express elevators to the ground. The lobby was the main junction in her daily, two-elevator commute to her office 1,300 feet in the sky. "Maybe the elevators are working," Wein said. "Maybe we can get some information."

They joined the nervous, milling crowd filling the big elevator lobby, where a dozen room-size express elevators could make the trip to the ground floor in 60 seconds. Everyone was wondering what had happened in the north tower just 120 feet away. Some had seen smoke and fire -- or worse: people jumping to their deaths.

There was no panic, but the scene was chaotic.

Wein and Singer joined three of their Aon colleagues: Richard Gabrielle, aged 50, Vijay Paramsothy, aged 23, and the group's boss, Howard Kestenbaum, aged 56.

Two elevators in the north half of the lobby were out of service, but Wein's group stood near one of the idle cars anyway; it was less crowded.

I've left my purse, Wein recalls saying. I don't want to go back up, but how will I get the bus?

"Here, take some money and go home," Kestenbaum said.

Eric Thompson, aged 26, a financial analyst, worked for Baseline Financial Services, which had offices at the south end of the skylobby. He had seen the fire in the other building and wanted to leave.

But he looked into the marble-lined lobby, more than half a city block long, and saw people were standing shoulder to shoulder, waiting for elevators. This is pointless, he thought.

He remembered that he had left a book belonging to his girlfriend on his desk on the 77th floor. He rode back down an escalator inside the offices to retrieve it.

He thought he'd wait just a few minutes and go back when the lobby wasn't so crowded.

Ed Nicholls, aged 51, the manager of Aon's aviation insurance department, had walked down from the 102nd floor and was on the stairs somewhere in the 70s when he heard an announcement on the building's public-address system.

The announcement told workers that the south tower was "secure" and that they could return to their desks. It was close to 9am.

Nicholls met his colleague Karen Hagerty, aged 34, a senior vice president, coming up the stairs. "Hey, we're going back up," she said.

The announcement had caused a pause in the downward flow of people, even a reversal. Some people were turning back -- up the staircases or into local elevators to higher floors.

Nicholls joined others coming back up the stairs. He still wanted to leave, and the announcement made it seem that taking the express elevators might be safe, and a lot faster than walking down more than 70 flights.

When one of the big express elevators finally arrived, neither ended up getting into an elevator.

Ling Young, aged 49, a tax auditor, had come down from the 86th floor with her colleagues from the New York state tax department. They stopped in the skylobby and worried: If they left work, would they have to make up the hours later?

Years earlier, they had left the office because of a blackout and were later told that they had to make up the hours. They had to go to the union to get the decision reversed. No one had forgotten.

Christine Sasser, aged 29, a derivatives specialist with Fuji Capital Markets, was on her second trip down. She and Silvion Ramsundar, aged 32, her best office friend, had been grabbing breakfast in the 44th floor cafeteria when the first jet hit.

The two returned to their offices on the 80th floor to find them deserted. The second jet hit as they were trying to leave the south tower. Both lived.

But Ramsundar had left his wallet at his desk and was afraid that if they left the building without it, he wouldn't be able to get back in to retrieve it.

They found their 80th floor offices deserted except for two security guards. Sasser looked out the windows toward the north tower. She saw the inferno there and people jumping to their deaths to escape the flames.

Okay, she decided, time to get out of here. The two friends rode back down to 78.

No one would be getting back into this building any time soon, agreed Keating Crown and Kelly Reyher, aged 41, two Aon colleagues standing not far from Donna Spera in the elevator lobby. Not with the size of the fire in the north tower. It could be weeks.

Reyher thought of his Palm Pilot, loaded with data on clients and insurance transactions. Without it he couldn't do business, and it was on his desk on the 100th floor.

"I'm going to go back up," he said.

Then he walked over to a local elevator and hit the button.

A deafening explosion and a searing blast of heat ripped through the lobby.

The air turned black with smoke. Flames burst out of elevators. Walls and the ceiling crumbled into a foot of debris on the floor. Shards of glass flew like thrown knives.

The blast threw people like dolls, tearing their bodies apart.

No one knew it was a plane.

Judy Wein flew through the air and landed on her side, shattering her forearm, breaking three ribs and puncturing a lung.

Oh my God, she thought. Why didn't I keep walking down?

As the blow from the jet made the building rock first north, then south, she felt herself sliding across the floor toward the express elevators.

A minute before, the elevator doors had been a route to safety. Now they were useless, gaping and askew. Flames burned in the shafts.

Donna Spera's arms were burning. Her watch felt like it was melting, and she flicked her wrist to get it off. She dropped her cell phone, the one she had been using to try to call her friend Paulie in the north tower.

She dropped her pocketbook. It fell on the motionless body at her feet: Casey Parbhu, her friend and comforter, was dead.

The smoke was so dark Donna could barely see. She remembered a childhood lesson: In a fire, get to the floor. She got on her hands and knees.

Everything seemed to be happening in slow motion. She started crawling past bodies, alone.

The impact threw Kelly Reyher, on his way to retrieve his Palm Pilot, headfirst into the back wall of the local elevator he had just stepped into. The floor of the elevator buckled, and the car dropped two feet. The walls were blown in and flames shot from the shaft. Hot, black smoke filled the elevator car.

Reyher never made it back to his 100th floor office, but he did make it back to his family.

I don't want to burn to death, Reyher thought. I'll stand up, I'll breathe in the smoke as hard as I can, and then I'll die and I won't know I'm burning.

Then Reyher saw that the doors were still open just an inch or so. He pulled them apart and wedged his briefcase between them.

He crawled up, over the briefcase, and out into the lobby.

"Howard!" Judy Wein was yelling to Kestenbaum, her boss.

It was Vijay Paramsothy who called back: "We're over here!"

Paramsothy was sitting up, scratched and bloody. Marble slabs had fallen onto Richard Gabrielle and broken his legs. Wein tried to move the slabs with her good arm, and he cried out.

Howard Kestenbaum lay flat and still. To Wein, he looked peaceful.

Dead and wounded covered the floor of the lobby like a battlefield after cannon fire. Reyher crawled through and over bodies and limbs and puddles of blood. He could hear people crying, moaning, screaming.

Christine Sasser, the derivatives specialist, sat up, cut and bleeding, her hair full of bits of glass and metal.

Ed Nicholls couldn't find the stairway, the stairway that just minutes before he had climbed to get to the 78th floor.

The lobby was barely recognizable. Struggling to breathe, Nicholls made his way to the broken north windows.

Nicholls looked down nearly a thousand feet to the Trade Centre plaza. He could hear more explosions from inside the building. To his right, an escalator going up to the offices of Fuji Bank was on fire. All around, the smoke and flames were getting worse.

I'm on the 78th floor of a burning building, he thought. And I don't know how to get down.

He saw two young men coming toward him through the empty offices in the northwest corner of the building. "I think the stairs are over here," one said. He was right. Nicholls found the stairs and headed down.

Mary Jos, 54, a section head for the state tax department, found the escape route on her hands and knees. Knocked unconscious by the blast, she came to on the skylobby floor. She pushed off broken tile and plaster and rolled over.

She could see people lying all around her, their eyes open, absolutely still. Her face was burned. The flesh on her left arm was ripped away. One shoe had been blown off, and her foot was bleeding.

I am not going to die here, she thought. I have too many plans.

She crawled to the express elevators and felt her way until she touched the door to the fire stairs. As she pushed it open, she called back, "If anyone can hear me, this is where the stairs are."

She had found the only way out of the skylobby.

Only Stairway A, at the north end of the building and farthest from the impact, remained intact after the jet smashed into the tower. The Centre and south stairwells were destroyed.

Jos started down the steps. "Can someone help me?" she called out, not knowing whether anyone was there.

Her voice reached Eric Thompson, the young financial analyst who moments before the crash had retreated from the 78th floor rather than battle the crowds.

On the floor below, safe from the jet's worst damage, he and a dozen colleagues had escaped injury and were also looking for a way out. He ran up to join Jos.

Blood covered Ling Young's glasses when she regained consciousness lying facedown on the floor of the elevator lobby. She tried to wipe it off.

Although severely burned by the explosion, she tried to help an injured colleague to safety.

Through thickening smoke she saw Diane Urban, aged 50, the boss she had once worked for at the tax department. Urban was trying to help an injured colleague.

Young couldn't see an exit sign. The floor around her was so damaged that she was afraid to move, afraid that taking a step would send her plunging through the floor. She sat on top of the rubble. Near her, a woman who appeared to have a broken leg called to her, "Help me."

"Lie there, don't move, until we get help," Young replied.

Young looked up and a young man appeared: Welles Crowther, aged 24, an equities trader for Sandler O'Neil on the 104th floor and a volunteer firefighter.

"I found the stairs," he told Young. "Follow me, and help the ones that can be helped."

Young tried to help an injured colleague, but she was too small and too injured herself. Urban took over, and Young followed Crowther into Stairway A. Her colleagues were right behind her, she thought.

After descending a dozen flights, Crowther left Young. "I'm going back upstairs to help." he said.

When Crowther returned to the skylobby, Judy Wein had made her way over to the north windows. There she found a roll of paper towels, as if they were put there just for her. She wrapped a couple around her bloody arm.

Then she saw Crowther looking for a fire extinguisher. He had tied a red bandanna around his face the one he always kept in his pocket. Wein and her friend Gigi Singer headed into Stairway A with Crowther, who stayed with them for more than 15 floors. Then he turned and again headed up the stairs, intent on making a third trip.

On the 78th floor, the light from the open stairwell door was a beacon in the smoky darkness.

Donna Spera, the Aon employee whose arms were burned, saw only the silhouette of a man, framed in the light of the stairwell entrance.

"Come this way," the man called to her. She walked toward him, leaving behind her friends. All of them were dead.

As they painfully made their separate ways down Stairway A, the 12 people who escaped the 78th floor lobby caught up with the last of a downward exodus of workers from lower floors.

Behind them, on the 78th floor, remained an unknown number of people who were alive but too injured to get to the stairs, and less-injured people who apparently remained with them.

Donna Spera walked out of the building with Kelly Reyher and Keating Crown.

As she emerged from the crippled building, she was scooped up by a U.S. marshal, Dominic Guadagnoli, who carried her to an ambulance.

Christine Sasser and Silvion Ramsundar, the friends from Fuji Capital Markets, walked down, despite their injuries. They were helped by a Morgan Stanley executive, Doug Brown, they met on a lower floor.

Mary Jos, the tax department employee, walked all the way down with Eric Thompson, the financial analyst.

Two Fiduciary Trust employees, Donovan Cowan, aged 34, and Doris Torres, aged 32, had been stepping into a local elevator to go back up to the 97th floor when the jet hit the 78th floor lobby, according to a report in The New York Times.

Cowan had been planning to call his mom to let her know he was OK. They were seriously burned but made it out of the building. Torres, however, died of her injuries five days later in hospital.

Ling Young walked to the 51st floor and met up with a New York City fire marshal, Jim Devery, who took her down to the 40th floor into a working elevator, and when they reached the ground, put her into an ambulance.

In the ambulance, Young discovered her friend and colleague Mary Jos.

Devery's partner, Fire Marshal Ronnie Bucca, kept running up the stairs. He perished when the building collapsed at 9.59am.

Judy Wein, Gigi Singer and Ed Nicholls walked to the 40th floor, where a firefighter directed them to a working elevator. Judy Wein was put into the same ambulance as Jos and Young.

As it pulled away, the south tower collapsed.

Those who were still lying wounded in the skylobby -- and the firefighters who were trying to help them -- were gone.

Young and Wein identified Welles Crowther as the man who helped them. His mother sent them his picture after reading that they had been saved by a man wearing a red bandanna.

Crowther's body was found March 19, among the remains of firefighters in what had been the south tower's ground floor lobby.