The sky was clear and blue. The gray towers stood, both guarding and welcoming, at the gateway to the nation. Out of nowhere came the impact, the blaze, the smoke -- and then the towers were gone. When the dust and flames finally cleared, a new world had emerged.
The death and destruction defined that late summer day and remain seared in the minds of those who lived through Sept. 11, 2001. From the ashes and wreckage rose a new America: a society redefined by its scars and marked by a new wartime reality -- a shadow darkened even more in recent days by the resurgence of fundamentalist Islamist rule in the far-off land that hatched the attacks.
Twenty years later -- with more than 70 million Americans born since the crucible of the attacks -- the legacy of 9/11 remains. From airport security to civilian policing to the most casual parts of daily life, it would be nearly impossible to identify something that remains untouched and unaffected by those terrifying hours in 2001.
This week, ABC News revisits the 9/11 attacks and unwinds their aftermath, taking a deep look at the America born in the wake of destruction. "9/11 Twenty Years Later: The Longest Shadow" is a five-part documentary series narrated by George Stephanopoulos. Episodes will air on ABC News Live each night leading up to the 20th anniversary of the attacks, from Sept. 6-10. The series will be rebroadcast in full following the commemoration ceremonies on Saturday, Sept. 11.
MORE: 'The Longest Shadow' Part 1: 20 years later, 9/11 families seek justice -- and peace MORE: 'The Longest Shadow' Part 2: A radical post-9/11 government overhaul pits security against liberty MORE: 'The Longest Shadow' Part 3: After 20 years at war, one question remains: What was it for? MORE: 'The Longest Shadow' Part 4: Guantanamo Bay and a new rulebook for a new warThe blue light may have been the strangest part.
On the streets of Baltimore, where crime proliferates in the poorest neighborhoods and economic desperation can run thick, the blue cast made it feel like one of those science-fiction movies set in a dark future of robots in control.
"I found it extremely oppressive and dystopian," said Joanne Cavanaugh Simpson, a contributor to Baltimore magazine and a Pulitzer Center grantee.
The blue lights are meant to be seen. They are security cameras, and police want them to both solve crimes and deter them. In the city famed as the birthplace of America's national anthem, the lights announce that the people are being watched.
Critics say these neighborhoods coated in blue also represent something else: the failures of an overzealous surveillance state, militarized and armed to the hilt in the years since terrorists attacked the nation on Sept. 11, 2001.
Despite the city's high-tech efforts to curb crime, Baltimore still suffers from some of the highest homicide rates in the country. The city's public image -- shaped for many by the HBO crime drama "The Wire" -- remains tethered to the fraught relationship between the police and the community.
For Baltimore and other major metropolitan areas, ubiquitous surveillance and a tragic cycle of police-involved killings continue to animate the debate over U.S. law enforcement. Many of the most controversial policing practices date to 9/11, when local governments were flooded with a surge of money, technology and new crime-fighting strategies -- on top of a new mindset that assigned local cops to the front lines of the Global War on Terror. It was a time when many police departments re-fashioned themselves as paramilitary organizations, as their core mission was recalibrated from performing the traditional role of "protect and serve" to preventing the feared "second wave" of attacks for a terrorized and traumatized nation.
Police departments across the country, eager to avoid the failures that led to 9/11, scrambled to equip officers with the latest in military equipment and technology -- much of it made available by a federal government that would spend almost 20 years at war in Afghanistan and Iraq. And the police forces -- always eager to hire military veterans -- were being staffed by people trained to police populations under occupation, not communities on the home front who get to decide how they want to be governed. Critics charged that racial profiling proliferated in cities like Baltimore, where the blinking blue lights became a symbol of life under a surveillance state.
"Over-policing, the racial tension -- it just exponentially grew for local policing," said Chris Burbank, a former police chief in Salt Lake City, who's now a vice president at the Center for Policing Equity.
From aerial surveillance in Baltimore to national terrorist watch lists, local police departments experimented with novel approaches to securing their streets in the years following 9/11. A scarred nation largely acquiesced.
Over time, critics of these methods say that the trauma suffered by heavily policed communities -- and the toll on residents' civil liberties -- have done more harm than good. As protests erupted across the country in the wake of George Floyd's death in 2020, the gap between police departments and the citizens they are sworn to protect had never seemed wider.
"This separation between policing and community, I think you have to view 9/11 as gasoline that was poured on that fire," said Lawrence Grandpre, a Baltimore-based community activist and author.
In the immediate aftermath of 9/11, a wariness of Muslims swept the country. Hate crimes against Muslims skyrocketed. Mosques became inundated with threats.
"Anything that showed that you were an Arab or a Muslim caused everyone to be suspicious of you," said Sahar Aziz, director of the Center for Security, Race and Rights at Rutgers University Law School.
MORE: Feds Spied on Prominent Muslim-Americans, Report ClaimsIn response to the terror attacks, police departments in some major cities compiled vast databases of alleged potential terrorists and undertook ambitious surveillance missions targeting Muslim communities.
"You had massive surveillance programs by the NYPD, and the LAPD, and the FBI," said Aziz. "Muslim student organizations at universities, Muslim-owned businesses, mosques, anywhere where Muslims congregated was systematically surveilled … we were sitting ducks."
At the time of the attacks, the conversation around law enforcement was trending toward stricter guidelines for equitable policing -- including halting some of the most invasive tactics like stop-and-frisk. Years of advocacy and lobbying in Washington culminated in the End Racial Profiling Act -- a bill incoming President George W. Bush supported on the campaign trail in 2000.
"And then 2001, 9/11 happened, and it was completely off the table," Aziz said. "It was a nonstarter."
Before the 2001 terror attacks, John Farmer was the New Jersey attorney general who led the push to reform a state police culture that had itself acknowledged racial profiling and had vowed to eliminate it. After the attacks, as Farmer served as senior counsel to the 9/11 Commission, he said he had to watch as 9/11 "had the effect of deferring the debate on racial profiling."
"Suddenly," Farmer said, "no one wanted to talk about it anymore."
Over the next decade, as American military forces engaged terrorists abroad, veterans of war returned home to continue their service as police officers. Together, with the influx of weapons of war, police throughout the U.S. began to look more and more like they were deployed on a forward operating military base.
"Police departments all over the country have acquired a pretty significant amount of military-grade weapons and equipment since 9/11," said Loren Crowe, an Army officer who served two deployments overseas. "My local police department would be well-equipped to go fight in the mountains in Afghanistan."
MORE: Ferguson Police's Show of Force Highlights Militarization of America's CopsIt all amounted to a post-9/11 "over-policing" that has had debilitating effects on police-community relations, according to many who have spent their careers in law enforcement.
"At that time there was so much fear in communities because of 9/11," said Baltimore Police Commissioner Michael Harrison, who experienced the changes as he worked his way up through the ranks in the New Orleans Police Department. "And it became a concept of more police -- and do more with more police."
In Baltimore, where the death of Freddie Gray in 2016 ignited nationwide protests and added new urgency to the debate over post-9/11 policing, the local police department led the charge in advancing novel and controversial police tactics.
Blue-light cameras flooded crime-prone streets. Facial recognition software and phone data collection were employed to fight crime.
Perhaps the most jarring to residents were the so-called "spy planes" deployed to surveil large swaths of the city. Launched in 2016, the nation's first-ever aerial surveillance experiment was meant to be secret. The manned airplanes' immense capabilities allowed them to record the outdoor movements of an entire city. An independent audit later found that nearly all of the spy planes' flights tracked over majority Black communities.
The police department has since suspended the program, and Harrison, the new commissioner, is focused on mending the strained relationship between the police and the community.
"Let's try to tamper down the militaristic look and mindset, and move away from the warrior model into the guardian model, where we're guardians of our community, not necessarily warriors of the community," says Harrison.
Still, wounds run deep.
"Baltimore is one of the cities that is a pioneer in surveilling its own citizens," said Simpson, who has reported on the city's surveillance programs for Baltimore magazine. "There's a lot of desperation to get a handle on the crime … so Baltimore has become a destination for police surveillance technology companies, to try out their wares."
Grandpre, the community organizer, said this experimentation with electronic surveillance "just exacerbates the notion of a divide between the police force and the community."
"After 9/11 and with Baltimore's high crime rate, there's a notion that anything is acceptable," Grandpre said.
Now, two decades on, Americans are finally returning to pre-9/11 conversations about policing and what it really means for a nation to govern itself.
"Absolutely there's bias. Absolutely there's racism. And we can start to talk about some of these things," said Burbank.
Supporters of these police programs stress the need to try something new and different. "What we've been doing has not been working," said Joyous Jones, a retired nurse and proponent of police surveillance in Baltimore, who decided to start working for the surveillance company running the planes after the program became public.
"The [American Civil Liberties Union] and all those people that really complain about their civil liberties -- I don't have that because when I walk outside, I have to look and dodge bullets," Jones said.
Jones is not alone in her support for the programs. "There was public support for it," Commissioner Harrison said. "There were community surveys that were in high percentage in favor of it ... and we looked at all of that."
But after a year of high-profile police-involved killings and a spike in violent crime in many cities, reformers continue to ask: Are these police practices even working?
"People talk about the dichotomy: Do we want security, or do we want liberty? But some of the experts I spoke with say that's sort of a false dichotomy," Simpson said. "Are you getting more security with this technology? Is the crime rate in Baltimore getting better? No."
"All these technologies have been added, a lot of them since 9/11," Simpson said. "And what are you losing by deploying all this?"
ABC News' Sarah Kate Caliguire, Alexandra Myers, Abigail Roberts and Tom Sampson contributed to this report.