Thirty years ago today, terrorists left a bomb weighing more than a half-ton in a rented van parked beneath the World Trade Center, a workplace for tens of thousands. Its smoldering fuse took about 12 minutes to close the gap between the everyday and the horrific.

The lunchtime blast left a crater several stories deep, sent acrid smoke up the center’s north tower and killed six people. More than 1,000 others were injured that day, including a dark-haired trader just yards from the underground detonation.

Eight years later, that same man, Tim Lang, fled Lower Manhattan as terrorists struck the World Trade Center again, this time with jetliners. He saw the first of its two towers buckle and fall in an attack that killed nearly 3,000 people, including those dear to him.

Mr. Lang is 69 now, with shock-white hair and photos of grandchildren stored in his smartphone. He describes himself as an unremarkable man. Yet he is also an everyman through-line between two remarkable events: the attacks of Sept. 11, 2001, which upended world politics, and the bombing of Feb. 26, 1993, which is less indelibly burned into collective memory but stands as ominous prelude.

“Just about everybody forgets about it,” he said.

Not Mr. Lang. He continues to process what happened — while working to push against feelings of hate that might consume him as easily as the burning hole left by the bomb. “There’s a saying,” he said. “Resentment is like taking poison and hoping the other person dies.”

Still, that February Friday and that September Tuesday have become part of him. He dreads the anniversaries.

“In the days leading up to it, I don’t sleep,” Mr. Lang said. “And that’s already begun. February’s here. So I have trouble.”

In the winter of 1993, Mr. Lang was succeeding on Wall Street and foundering in nearly everything else. He was the about-to-be-divorced father of two boys and two girls, alienated from devout Roman Catholic parents who believed in the sanctity of marriage. Now Tim, the fourth of the dozen children they had raised in working-class Brooklyn, was living alone and feeling alone.

He hadn’t wanted to go into the city that day, but his partner insisted he was needed at a 12:30 meeting. A reluctant Mr. Lang left his New Jersey condo and drove his Toyota 4Runner through the cold, late-morning gray.

As he headed down a ramp into the World Trade Center’s underground garage, a zooming Ford Taurus cut ahead of him. After a brief wait, the two vehicles entered the garage, the Ford making a right and the Toyota turning left.

If Mr. Lang saw the Ryder van parked on the same level, he took no notice. He pulled his S.U.V. beside a concrete wall, got out and opened a back-seat door to collect his coat and some documents. Then came a crack like a lightning strike.

He felt his entire body compress as he was lifted and thrown. His head hit something, and he was out.

Mr. Lang awoke to blackness, thick smoke burning his throat and dozens of car alarms bleating in his ear. He checked his legs and arms and felt a sticky wetness at the back of his head. His inability to see had him briefly thinking, of all things, that he was now the second blind bagpiper in his pipe band.

Thoughts like these jumbled in his mind. Had the car beside him exploded? Was this mob-related? What about that page from a calendar of biblical sayings he had stuck in his wallet that morning? Genesis: Do not be afraid.

Coughing and too dizzy to stand, Mr. Lang crawled through the jagged debris to a distant light — he could see! — coming from what turned out to be his Toyota. He climbed inside to drive away, only to realize it was crumpled.

Low to the ground and with his sweater pulled up over his nose, he tried to find an exit. Familiar with the garage’s layout, he made his way toward the destroyed manager’s office to find a phone, fell on a dead body, then crawled to the edge of the smoldering chasm created by the explosion.

“So if things were bad where I was before, this pit is spewing out stuff from the bottom of hell,” Mr. Lang recently recalled on “Operation Tradebom,” a podcast about the bombing.

He crawled away, lay down by a car, prayed for his children and for the courage to die. A calm began to settle over him. Then a bang sounded in the distance.

“And I screamed out,” he said.

Someone hearing his cries alerted two members of the New York Police Department’s Emergency Services Unit who arrived early to the scene: Detective Edward Joergens and Officer Cory Cuneo. Wearing air packs and using a fire hose spooled near a door as a tether, they inched through the consuming darkness.

“We carried these huge flashlights, and still you couldn’t see six inches in front of you,” Mr. Cuneo recalled.

Their lifeline of a fire hose ran out, but sporadic calls for help beckoned above the car-alarm cacophony. They pushed on.

Minutes later, a rescuer’s boot illuminated by a flashlight appeared before Mr. Lang, and he grabbed it. Finally: connection.

The hope that he might survive competed with the fear that he couldn’t breathe — and what he was breathing was toxic. He clutched Mr. Cuneo’s hand.

“I would not let go of his hand,” Mr. Lang recalled. “I was shaking and crying and would never let go of his hand.”

With two supporting one, the men stumbled and banged their way through the murk. Finally, they reached a stairwell, and daylight and Liberty Street, where the soot-covered man in shock was gently lowered to the sidewalk.

After several hours in the hospital, Mr. Lang returned to his isolation along the Jersey Shore. “It was the darkest time of my life,” he said. “Now, I can look back and say, you know, the Lord can nudge you along, or he could have you blown up to make it right.”

Mr. Lang would sit at water’s edge, grateful to be alive — glad just for the coffee in his hand — but grieving, too, for the loss of other lives, for the state of things, for his own state. He thought about that line from Genesis and about that driver of the Taurus who had cut him off, turned right and was killed. Sometimes he cried.

“Whatever my priorities were, they changed when I came out,” he said. “Like so many balls thrown up in the air and landing in a different order.”

It took time to understand the new order. He found a therapist. He committed himself more deeply to his faith. He reconciled with his parents and siblings. He remarried and became the father of two more girls.

He also did a lot of reading about radical Islam. “Who are these people?” Mr. Lang said he wanted to know. “And why did they try to kill me?”

He learned that the mastermind of the bombing, Ramzi Ahmed Yousef, had been disappointed with its death toll and had hoped that the north tower would topple into the south tower.

“I always knew they’d be back,” Mr. Lang said.

Mr. Yousef, who fled the United States hours after the bombing, would team up with his maternal uncle, Khalid Shaikh Mohammed, who had sent money by wire transfer to one of Mr. Yousef’s co-conspirators. Plots of terror continued.

Mr. Yousef was captured in 1995 and eventually convicted in the trade center bombing and a subsequent plot to down several American airplanes. He is serving life without parole in a federal “supermax” penitentiary in Colorado.

But his uncle continued to elude capture. And on the morning of Sept. 11, 2001, Mr. Lang and his brother Richard were walking into their Lower Manhattan building when someone said a plane had hit the World Trade Center’s north tower. Hustling out to Rector Street, they saw the point of impact and the ensuing fire — just below where their sister Rosanne worked as an equities trader.

The brothers raced up to their high-rise office and tried telephoning her. No answer. They then heard a tremendous ground-rattling sound and looked out to see the second jetliner fly past and into the south tower.

Fearing more attacks, the Lang brothers made it to Pier 11 at the eastern end of Wall Street and boarded one of the first ferries evacuating people to New Jersey. As the vessel pulled away, they saw the south tower fall.

“We have to pray,” Mr. Lang recalled saying.

The men did not yet know that their nephew Brendan, 30, a project manager for a construction company, was among those killed in the south tower’s collapse. And as their ferry approached the dock in Highlands some 40 minutes later, the captain announced that the north tower had fallen as well.

Four of the Lang brothers — Tim, Richard, Donald and Marty, a just-retired New York firefighter — headed out the next day to Lower Manhattan, hoping to find their loved ones alive. But they knew.

Rosanne Lang, 42, was the divorced mother of a teenage son. A glimpse of her effect on others came when Mr. Lang and a brother went to collect her Mercedes at her usual parking lot in Jersey City. He pointed out the car and the attendant burst into tears.

Federal authorities have identified Mr. Yousef’s uncle, Mr. Mohammed, as the principal architect of the Sept. 11 attacks. Captured in 2003, he has been held since 2006 at a military prison in Guantánamo Bay, where efforts to prosecute him have been delayed by a host of complications, including his torture at the hands of the C.I.A.

In 2019, Mr. Lang was part of a group invited by the federal government to observe proceedings at Guantánamo Bay. Seeing Mr. Mohammed up close, in custody, he felt no hate, he says — only a deep sadness over lost lives, wasted lives and belief systems that allow for the killing of innocent people in retaliation.

“There’s a complexity to other people’s lives that is beyond my own understanding,” he said.

These days, Mr. Lang runs an equity trading firm, Global Liquidity Partners, from an office near his home in Monmouth Beach. He golfs, attends a men’s prayer group, plays the bagpipes, marches in parades and enjoys the company of his seven grandchildren, all boys.

The years come and go, as do anniversaries.

A few days ago, on Ash Wednesday, Mr. Lang went to a Catholic church and received the gray smudge on his forehead to remind him of, among other things, his mortality. Two other days on his calendar do the same.