I suppose my I'll-never-forget-where-I-was recollections are pretty typical: a half-curious pricking up of the ears when they cut into the morning show on the radio with breaking news about a plane hitting the World Trade Center - it sounded like a twin-prop or Lear Jet - and then the slow realization when the second plane hit that something bigger was going on. My editor called from London a few seconds later, and I switched on the TV. But even in the midst of unprecedented forms of mass slaughter, humdrum routine goes on for the rest of us: I was having some furniture delivered that morning, and the guy interrupted me to ask where I wanted one of the pieces to go, and when I turned back to the screen only one of the smoking towers was still there. "What happened?" I said. "It fell down," the delivery guy shrugged, and ambled back to his work. He was sort of right. It fell down, but it burned for another 100 days, as America's rage did - for some. For others, it was already fading, the "day that everything changed" already lapsing back into the feeble passivity of one of those one-off "tragedies," after which everything goes back to the way it was. What was taking place that Tuesday morning was, as a lot of people said, "unimaginable." But once it happened, once we no longer had to imagine it, my main memory of that day is of how quickly the mind leapt forward to encompass the new reality. When the second plane hit, it was obvious not just that this was no accident, but that it would be impossible to find two commercial airline pilots willing to fly, even at the point of a gun, their jets into skyscrapers. Which meant that, at the moment of impact, these flights must have been in the hands of terrorists who'd trained as pilots presumably for the purpose of this mission: They had acquired at least basic skills in a profession that would guarantee a good life anywhere on the planet; they could be pulling down six-figure salaries instead of Manhattan skyscrapers. But instead they went to pilot school in order to make one flight, one time, one-way, into a tall building. AND HALFWAY across the world, on the streets of Ramallah, people filled the streets and cheered and passed out candy. They celebrated at Concordia University in Montreal and in northern England and in Scandinavia, too, but I didn't find that out until e-mail from readers began coming through later in the day. In Afghanistan, Osama bin Laden and his colleagues followed events on the Arabic Service of the BBC. (Not all the BBC's output is in Arabic; it just sounds like it is.) As the years go by, it's these curious examples of cultural interconnectedness that stay with me. "Interconnectedness" is the word used by the late Edward Said, the New York-based Palestinian grievance-monger and eminent America-disparager: A couple of weeks after 9/11, the professor deplored the tendency of commentators to separate cultures into what he called "sealed-off entities," when in reality Western civilization and the Muslim world are so "intertwined" that it was impossible to "draw the line" between them. National Review's Rich Lowry was unimpressed. "The line seems pretty clear," he said. "Developing mass commercial aviation and soaring skyscrapers was the West's idea; slashing the throats of stewardesses and flying the planes into the skyscrapers was radical Islam's idea." Very true. But that may be the only "interconnectedness" a large part of the world is interested in: state-of-the-art technology in the service of ancient hatreds. Edward Said was right: there are no more "sealed-off entities." The "modern world" and the "primitive world" are more like those overlaid area codes the phone company's so partial to. So a man can roar Allahu akbar! as he ploughs his jet into an office building. Even the most primitive parts of the map aren't that "sealed off" these days. After all, why were they listening to the BBC's Arabic Service in Afghanistan? Afghanistan isn't an Arabic-speaking country. They parly-voo the old Pushtun and Dari and Turkmen and whatnot. But on September 11, 2001, the nation was, in effect, under colonial occupation by thousands of Arab and other foreign jihadists. We think of the badlands of the Afghan-Pakistani border as a remote region of isolated peoples whose rituals have been unchanged for centuries. Yet the truth is that these village tribal cultures have been wholly subverted by Saudi money and ideology. The House of Saud's toxic kingdom, a land where the beheading schedule is computerized, may be a more apt emblem of the way an "interconnected" world is heading than we like to think. ONE MAN in the Twin Towers that Tuesday morning must have understood. John O'Neill, a dogged counterterrorism guy with a whiff of the old-school G-man about him, had just quit the FBI and started work as head of security at the World Trade Center. He made it downstairs where the confabs with rescue workers were punctuated by the thud of bodies from the first jumpers landing on the lobby roof. In the plaza outside, body pieces fell randomly over chairs set up for a lunchtime concert. In the final moments of his life John O'Neill must have felt his world come full circle. Six years earlier (as vividly recounted in Lawrence Wright's The Looming Tower) he'd organized the capture in Pakistan of Ramzi Yousef, the man behind the first World Trade Center bombing and a terrorist who'd planned to crash a plane into CIA headquarters. In The New York Times,Thomas Friedman wrote: "The failure to prevent Sept. 11 was not a failure of intelligence or co-ordination. It was a failure of imagination." That's not really true. Islamist terrorists had indicated their interest in US landmarks, and were known to have plans to hijack planes to fly into them. But men like John O'Neill could never quite get the full attention of a somnolent federal bureaucracy. The terrorists must have banked on that: after all, they took their pilot-training classes in America, apparently confident that, even if anyone noticed the uptick in Arab enrolments at US flight schools, a squeamish culture of political correctness would ensure nothing was done about it. FIVE YEARS on, half America has retreated to the laziest old tropes, filtering the new struggle through the most drearily cobwebbed prisms: All dramatic national events are JFK-type conspiracies, all wars are Vietnam quagmires. Meanwhile, Ramzi Yousef's successors make their ambitions as plain as he did: They want to acquire nuclear technology in order to kill even more of us. And, given that free societies tend naturally toward a Katrina mentality of doing nothing until it happens, one morning we will wake up to another day like the "day that changed everything." September 11 was less "a failure of imagination" than an inability to see that America's enemies were hiding in plain sight. They still are.