Random memory of Sept. 11, 2001: Late on that grim day, I was biking home from downtown. Coming up the hill toward Columbia Heights on 13th Street NW, I stopped near the intersection with Clifton Street. The corner is one of the District’s most magical vistas. Staring south, you see the full federal skyline, punctuated by the Capitol dome looming in the distance. It’s a man-made landscape, of course, but for a native it can feel as permanent as the mountain ranges that frame other cities. That evening, with the fourth jetliner having crashed in a field in Pennsylvania, it suddenly stopped seeming that way.

Unlike New York, Washington did not have its physical appearance transformed by 9/11. To this day, there’s a hole in Manhattan’s skyline. Even now, you have only to turn your head as you emerge from the Lincoln Tunnel in order to see Osama bin Laden’s murderous handiwork. Here, on the other hand, the part of the Pentagon his henchmen struck was comparatively low to the ground and out of view. His final target was unharmed. There’s no empty sky; the cityscape beyond 13th and Clifton is unchanged. But our sense of the city’s permanence is not quite the same. I was reminded of that a couple hours before Osama’s death was announced on Sunday, when I dropped a friend off at her apartment a block to the north.

Of course, as anyone who’s ever had to show their ID in order to get into their dentist’s office building downtown knows, our urban landscape has changed in smaller ways. This is hardly the responsibility of bin Laden alone. The late ABC newsman David Brinkley’s book on Washington during World War II paints a picture of a prewar city where office workers took their lunch on the White House lawn. The history of our move away from that unfenced metropolis to our current town of Jersey barriers and Metrorail bag checks is a long one, its path blazed by Pearl Harbor bombers and Cold War spies, lone gunmen and obscure conspirators, Lee Harvey Oswald and John Hinckley and Timothy McVeigh.

Bin Laden’s contribution to the Washingtonian condition—like his broader contribution to the American one—was to hammer home the notion that civilians weren’t just collateral damage. Growing up in D.C. in the Reagan years, we kids were reassured by our parents that the Soviets wouldn’t send missiles here: The logic, which may not have been right but which was certainly reassuring to a 10-year-old, was that the Commies would want to have a government with which to negotiate after they’d wiped out Kansas City and Denver. But in the last nine and a half years, there was no sense that the bad guys adhered to that sort of thinking. To the contrary: They wanted to attack symbols, and ours is a city full of them. So every stadium outing and subway ride and mass gathering on the Mall came with a kind of asterisk.

In the years that followed, we generally accepted even more of the minor indignities of the permanent security apparatus, from metal detectors at museums to D.C. Council types demanding in-case-of-emergency SUVs. And even as terror receded from both the municipal and national conversations, most of us, I think, still have the sense that the mask of modern District life could get yanked off in less time than it takes to queue up for a Georgetown cupcake: Schools, businesses, and editors of local alt-weeklies all mull contingency plans for that horrific future day when people are again hoofing it home because the Metro is closed and the cell phone network is inaccessible and the panic is high.

In the early days after 9/11 and anthrax, drunk on comparisons to the virtuous struggle of World War II, locals analogized the new normal to London during the blitz. A decade later, with Osama drifting to the bottom of the Arabian Sea and new condos rising on formerly forlorn patches of Washington, it’s pretty clear how wrong some of the more gloomy portrayals turned out to be. We flattered ourselves with evocations of plucky Churchillians, but I’m fairly certain London didn’t see a long-term real estate boom while its houses were being bombed by the Nazis. Nor did its residents see a spate of stories about how their decaying city was in the midst of a historic revival.

Yes, every decision to relocate a business to the District, and every oversized down payment for a house here, was touched in the past decade by the shadow of bin Laden—a giant caveat making clear that another well-executed act of terror could undercut that investment. But people invested all the same, not just money but time and emotion, the stuff that makes people feel like they belong to a place, and vice versa. It turns out there is still a pretty healthy market for impermanence.