Though she has no independent recollection of her mother, Patricia Smith has spent 20 years missing and learning about her. Through stories imparted by relatives, family friends and Google searches, she has pieced her mom together like a shattered mirror reflecting an adventure-seeker who once ran with the bulls in Pamplona and swam across New York's Lake Placid.
"It's the only piece of jewelry of hers that I'll wear," Patricia Smith, now 21, said of the necklace. "I get so nervous that I'll lose something. I feel that I only have so many things of hers left that I want to keep all of it."
Saturday marks the 20th anniversary of the most lethal attack in history on American soil, a commemoration of the 2,977 people killed when 19 terrorists from half a world away hijacked and turned four commercial aircraft into missiles that rained death on New York City, the Pentagon and a field in rural Shanksville, Pennsylvania.
"When I talk about 9/11 to my students, I begin by explaining to them that it was really a life-changing event. It changed the way that our government works, its focus in terms of protecting the American people. It changed the way Americans live today," said former U.S. Attorney General Alberto Gonzales, the dean of Belmont University Law School in Nashville, who was White House counsel to then-President George W. Bush on 9/11.
"We obviously wanted Americans to live their lives as normally as possible, but to understand that we live and operate in a very dangerous world where there are people, there are organizations, there are groups that don't have very kind views about our way of life, about our values," Gonzales told ABC News.
More than 70 million born in U.S. since 9/11
More than 70 million people living in the United States, according to yearly birth data from the Centers for Disease Control and Prevention, had not yet been born on 9/11. Millions more, like Patricia Smith, were too young to comprehend the destruction and the metamorphosis that followed.
The war in Afghanistan spanned the administrations of four presidents and the eight-year Iraq War, only to end last month with the chaotic withdrawal of American troops and the deaths of 13 more military service members, four born the same year as 9/11. The Taliban, which controlled Afghanistan in 2001 and provided safe haven to al-Qaeda, is back in power, renewing fears the country will once again become a base for terrorism.
Loren Crowe was a student at Columbia University on 9/11, joined the Army after graduating in 2005, and served two tours in Afghanistan that garnered him two Purple Hearts. Yet, he said he understands why many who served in combat question if it was worth the pain they witnessed on both sides of the wire. He said he can only hope his fellow platoon members who didn't make it back alive "died for something greater," and that he tries to see the positives through the bleak saga of Afghanistan.
"Some folks got an education that they might not have gotten. Some folks had access to health care that they might not have gotten. Was it worth it in the grand scheme of things? You know, who knows?" Crowe told ABC News.
"I think it's just desperately heartbreaking. And I think that more Americans should feel more shame about our lack of ability to provide a better future for them (the Afghans) over 20 years," Crowe said. "That's not any individual's fault. That's a large collective weight that I think probably we as a country need to carry."
While it's been 10 years since Osama bin Laden, the founder of al-Qaeda, was gunned down by SEAL Team 6 in Abbottabad, Pakistan, no one has been convicted of helping him carry out the diabolical plot he mastermind, and only one has pleaded guilty and sentenced to life in prison.
"Justice delayed is justice denied. And now we're 20 years later with no justice," Patricia Smith told ABC News on a recent visit to the memorial pools on the footprints of the twin towers, the 110-story buildings that took seven years to construct and less than two hours for terrorists to topple.
Death rains from a crystal-clear sky
When Officer Moira Smith departed her home on that fateful Tuesday and headed to the 13th Precinct in lower Manhattan, she kissed her 2-year-old daughter, Patricia, goodbye and left the toddler in the hands of her husband, Jim Smith, an officer working the night shift with the NYPD at the time. The father and daughter spent the morning watching Winnie the Pooh cartoons on a VCR unaware of the attack commencing.
At 8:46 a.m., Smith heard a thunderous noise overhead, looked up into the clear blue sky, and saw a wide-body Boeing 767 swooping perilously close to the world's most famous skyline. American Airlines Flight 11 plowed into the north tower of the World Trade Center, vanishing in a fireball between the 93rd and 99th floors. Smith is believed to be the first cop to radio in the catastrophic incident, the biggest salvo in the nation's never-ending war on terrorism.
Seventeen minutes later, a hijacked United Airlines Flight 175 crashed into the south tower.
As the twin towers burned, a newspaper photographer snapped a shot of Smith leading a well-dressed man, his head bloodied, away from the disaster before she headed back to help others. Moira Smith's desperate last radio transmission came from inside the south tower: "I don't have much air. Help me, please," she said, according to a recording of the dispatch.
"And that last transmission you can definitely hear it that my mom was suffering. And I have to live with that," said Patricia Smith, a recent graduate of the University of Alabama who works as an athletic trainer for the Tulane University football team in New Orleans.
'Get out of here'
American Airlines Flight 77, a Boeing 757 aircraft, took off from Washington's Dulles International Airport headed for Los Angeles when it, too, was hijacked. At 9:37 a.m., the once-unthinkable happened: The aircraft slammed into the west wall of the Pentagon.
United Airlines Flight 93 took off from Newark International Airport in New Jersey that morning headed for San Francisco. According to a report from the National Transportation Safety Board, a team of four al-Qaeda terrorists stormed the cockpit and at 9:32 a.m. the cockpit voice recorder indicated a struggle was occurring and captured the words of someone yelling, "Get out of here."
At an altitude of 41,000 feet, the plane suddenly changed course over northeast Ohio and began descending as it headed southeast. At least 13 passengers and crew members began calling loved ones on their cellphones and onboard GTE Airfones, reporting that the flight had been hijacked by four men wearing red bandanas and wielding knives, that a flight attendant was killed and a passenger stabbed.
According to the recordings, some of the passengers said they were formulating a plan to fight back. One passenger, Todd Beamer, was on the phone with a GTE Airfone operator who heard him say "let's roll" just before the aircraft nosedived over Somerset County, Pennsylvania, and crashed into a field in Shanksville, about 80 miles southeast of Pittsburgh.
Tom Ridge, who was then the governor of Pennsylvania and would be appointed the nation's first Secretary of Homeland Security in the aftermath of 9/11, told ABC News that he is certain the hijackers would have flown the plane into the nation's Capitol Building had the passengers not intervened and stopped the attack.
"Listen to the voicemails from the passengers. We know exactly what's going on," he said.
'America is under attack'
Andy Card, then the chief of staff to President George W. Bush, was with the commander-in-chief that morning at Emma E. Booker Elementary School in Sarasota, Florida, to promote the White House's "No Child Left Behind" education program. Before entering a room of children, Card recalled a Navy captain approaching him and the president to say a small plane had crashed into the World Trade Center, an unfortunate tragic accident they initially thought.
After the president began reading to the second-graders from the children's classic "The Pet Goat," the same Navy captain told Card a second plane had hit the World Trade Center towers.
Card said he immediately entered the room where the president was reading and whispered in his right ear, "America is under attack." Concerned about causing a panic, Bush remained in the classroom for several more minutes while the children continued to read, according to the 9/11 Commission Report.
On the way back to Washington, Card said he, Bush and other West Wing staffers watched in horror on television as the south tower of the World Trade Center, the second building struck, collapsed at 9:59 a.m. ET followed 29 minutes later by the pancaking of the north tower.
The following day, Bush traveled to lower Manhattan to see the destruction for himself. He stood atop a pile of smoldering rubble, his left arm draping the shoulder of a veteran firefighter, and began to speak into a bullhorn of the unspeakable loss. When someone in the group of rescuers and volunteer construction workers huddled around him shouted, "George we can't hear ya," the president responded, "I can hear you. The rest of the world hears you, and the people who knocked these buildings down will hear all of us soon."
For 20 years, former FBI agents Kenneth Williams and Mark Rossini said they have spent countless sleepless nights wondering what if their warnings had been heeded.
Two months before the 9/11 attacks, Williams, then an agent at the FBI's bureau in Phoenix, wrote what became known as the "Phoenix Memo" to his superiors at FBI headquarters that he had collected intelligence indicating bin Laden and al-Qaeda were getting ready to do something in civil aviation in the United States and associates of the terrorist network were attending flight schools in Arizona.
"I wanted this information to be discussed with the broader intelligence community," Williams told ABC News.
Williams' memo was never acted on because he suspects it did not include a specific threat or potential target. One of 10 suspected terrorists named in Williams' memo had close ties to Hani Hanjour, the hijacker who piloted Flight 77 into the Pentagon.
"I held nobody accountable for not really taking any action on that document because, at the time period, FBI headquarters was looking at real threat information that was coming in involving, for lack of a better description, ticking time bombs," Williams said.
In March 2000, Rossini was on loan from the FBI’s I-49 counterterrorism squad to the CIA's counterterrorism center at the agency's headquarters in Langley, Virginia. At work one morning, he read a cable from an informant saying two high-level al-Qaeda operatives had attended an al-Qaeda summit in Malaysia and entered the United States with valid visas in January 2000.
Rossini told ABC News that he encouraged his colleague, Doug Miller, to draft a cable to FBI headquarters because the al-Qaeda operatives entered the U.S. amid nationwide alarm over the “millennium plot” following the arrest of an al-Qaeda-trained operative with a car full of explosives in Washington State.
However, CIA officials who had to approve any information shared with the FBI barred Miller from sending his cable to the FBI. The CIA has never publicly explained why it blocked Miller's document.
The two al-Qaeda operatives were among the 19 Sept. 11 hijackers.
There was an enormous volume of intelligence shared with the FBI by the CIA, Rossini said, but why Miller’s memo wasn’t cleared to send to the bureau remains a 9/11-related mystery, numerous former officials from both agencies have told ABC News.
"This is my 20-year journey, trying to figure out why. I've had basically a nervous breakdown over it, if you really want to know the truth, rattling my brain why something simple was not done. It defies logic. It defies reason. You shouldn't accept it," said Rossini, who resigned from the bureau in 2008 when he pleaded guilty to misdemeanor charges of accessing records in an FBI database. He was sentenced to a year of probation, ordered to perform 250 hours of community service and pay a $5,000 fine.
Living casualties of the 'longest day in the history of days'
Among the voices emerging over the past two decades are ones of anger and distrust in the government over alleged secrets it refuses to disclose. Still, others, who raced to the ruins of the World Trade Center hoping to find survivors, continue to suffer and die from the toxic air government leaders insisted at the time was safe to breathe.
"9/11 is the longest day in the history of days," said construction worker John Feal, one of the hundreds of volunteers who rushed to the World Trade Center to search for victims. "It just has not ended for those that lost loved ones that day, for those who got sick and are still sick, for those who got sick and died."
Feal was severely injured during the search and rescue operation when 8,000 pounds of steel landed on his foot. He founded the FealGood Foundation, a nonprofit that advocates for New York first responders suffering from a host of ailments traced to 9/11 -- including lung disease, gastroesophageal reflux disease (GERD), cancer, post-traumatic stress disorder, pulmonary disease and depression. He has also lobbied Congress to extend compensation for them, even when some elected leaders no longer saw a need to.
"I'll be 55 in November. I was 34 when I got hurt. It's almost half my life," Feal told ABC News. "I wake up every morning and I'm reminded by looking at half-a-foot ... I guess time has evaded me because it feels like yesterday in so many ways."
Other living casualties of 9/11 are people like Brett Eagleson, who was 15 when his father, Bruce, was killed at the World Trade Center. Eagleson has spent years trying to get the federal government to make public what the FBI has learned about the roles top officials of the Kingdom of Saudi Arabia may have played in the attacks. A lawsuit he and other survivors of 9/11 victims filed against Saudi Arabia contends it was more than a coincidence that 15 of the 19 hijackers were from Saudi Arabia.
The 9/11 Commission Report completed in December 2004 found "no evidence that Saudi government as an institution or senior Saudi officials individually funded" the al-Qaeda hijackers. The Saudi Kingdom has denied accusations it was complicit in the 9/11 attacks.
"If there were Saudi officials who, in their spare time, were working with elements of al-Qaeda, that would not surprise me at all," former New Jersey Attorney General John Farmer, who served as senior counsel to the 9/11 Commission, told ABC News.
Leon Panetta, who served as secretary of defense and CIA director in the Obama administration, added: "Just as our country made mistakes in the judgments we made about 9/11, I think the leaders in Saudi Arabia made some of the same mistakes."
But the plaintiffs, whose case is pending, claim that since the commission's report was released, the FBI has continued to investigate whether the Saudi government was involved in 9/11 but has refused to declassify evidence the families suspect show the kingdom was complicit.
Last month, the Department of Justice announced that the FBI had recently closed a portion of its investigation into the attacks and is reviewing some long-classified documents to determine if they can now be disclosed. And last week, President Joe Biden signed an executive order directing the declassification of certain 9/11-related documents to be released over the next six months.
"The further and further we get away from 9/11, the easier it is to forget what really happened that day and the easier it is to forget about the truth," said Eagleson, whose father worked for the Westfield Group, which managed the mall at the World Trade Center.
The remains of Eagleson's father and those of more than 1,100 victims of the attack in lower Manhattan have never been recovered.
"That added to the pain and misery," Eagleson told ABC News. "My family, along with many other families, are still waiting on remains to be found."
'They destroyed my life'
Just 45 days after the Sept. 11 attacks, as the White House feared a follow-up ambush was imminent, Congress passed the Patriot Act, expanding the government's domestic surveillance powers to include reviewing bank records and even library accounts. The act also allowed the National Security Agency to execute warrantless searches of American citizens' phone calls and emails.
Subsequent lawsuits and whistleblowers such as Edward Snowden, a former computer intelligence consultant for the National Security Agency, revealed abuses of the act, including that the Bush and Obama administrations had secretly acquired in bulk the phone data of millions of innocent U.S. citizens without a warrant.
In the aftermath of 9/11, it also came to light that the U.S. government had allegedly kidnapped, detained and tortured numerous prisoners without ever charging them, including some of the more than 800 detainees sent to the Guantanamo Bay Detention Camp, an American military prison in Cuba outside U.S. legal jurisdiction that remains in operation.
“Anybody who does not know about Guantanamo I think today would be surprised at some of the things that went on there," Marion "Spike" Bowman, the former deputy general counsel for national security at the FBI, told ABC News.
Lakhdar Boumediene, an Algerian-born citizen, was held for seven years and six months at Guantanamo Bay, where he said he was relentlessly interrogated and routinely tortured.
The U.S. government has denied allegations of prisoners being tortured at Guantanamo.
"They destroyed my health. They destroyed my life," Boumediene told ABC News.
Boumediene said that he was living in Sarajevo, Bosnia, and working as an aide at a boarding school for orphans of the Balkan conflicts of the 1990s.
"I had a good life with my wife and children. I had a good job," he said. "And yet, my life had turned 180 degrees."
Following the Sept. 11 attacks, Boumediene was arrested in a sweep of men associated with an Algerian charity worker authorities suspected was plotting to bomb the U.S. embassy in Bosnia. When a judge ordered Boumediene released in 2002 for lack of evidence, he said he was inexplicably turned over to the U.S. military and sent to Guantanamo.
"They destroyed everything. But until now, I still didn't get anything. No compensation, no apologies. Twenty years later, I can't find the truth behind my imprisonment at Guantanamo," Boumediene said.
Boumediene became the lead plaintiff in a federal lawsuit by detainees accusing the Bush administration of denying them the right to habeas corpus, or the ability to challenge their detentions before a natural judge, in violation of the constitution. The U.S. Supreme Court in a narrow 5-4 decision sided with the detainees in June 2008.
Bush said he would abide by the high court's decision, but "that doesn't mean I have to agree with it." He said he strongly concurred with the dissenting justices, including late conservative Justice Antonin Scalia, who wrote that the decision would make the war on terror harder and that "it will almost certainly cause more Americans to be killed."
Four months after the ruling, Boumediene was released to France when federal Judge Richard Leon, a Bush appointee, ruled the Bush administration "relied on insufficient evidence to imprison" him and others deemed "enemy combatants."
From Sept. 11 to Jan. 6: Lessons unlearned
Panetta was the secretary of defense when bin Laden was killed on May 2, 2011. He recalled the relief that swept through the White House Situation Room and the chants of "USA, USA, CIA, CIA" coming from a crowd gathered across the street in Lafayette Park.
"I think we had sent a message to the world that nobody attacks the United States and gets away with it," Panetta told ABC News.
But a decade after bin Laden's death, America remains under the constant threat of terrorist groups that have metastasized around the world, and, according to Panetta, "without a comprehensive strategy to defeat terrorism in the world."
"I mean, you fight a war. You have an enemy. You go after that enemy. You defeat that enemy. And that's it," Panetta said. "In these instances, you're fighting essentially a guerrilla war in these countries with terrorists who are all over the place."
He said following 9/11, the U.S. had a clear mission to dismantle al-Qaeda and kill bin Laden.
"I think today, that memory has faded," Panetta said. "We're focused on other issues, health. We're now focused on China and Russia. I think it is very important for those responsible for protecting our country to never just go with the times, but to always ask the question: What are the potential threats that are out there?"
Tom Ridge, the former secretary of Homeland Security, said the Jan. 6 insurrection at the Capitol building, which caught police off guard, was an indication that some of the lessons learned from the intelligence breakdown of 9/11 have been forgotten.
"Are we going back to pre-9/11 complacency?" Ridge asked.
A former Republican governor and congressman, Ridge said the attack on the Capitol by American citizens was "shameful."
"But the fact is that Americans assaulted the Capitol when 20 years before Americans died so terrorists couldn't assault the Capitol," Ridge said. "If it isn't enough to make the hair on the back of your neck stand straight up ... well, at least it does mine."
ABC News' Alex Manalo-Hosenball, Brian Epstein, Olivia Rubin and Evan Simon contributed to this report.