* Photo: Vincent Laforet * At the southernmost end of Brooklyn, just off Dead Horse Bay, there's a weather-beaten helipad where the New York Police Department keeps a gray unmarked twin-engine Bell 412 helicopter. Detective Brendan Galligan ushers me aboard. "We don't really let people see this," he says.

We climb in behind the pilot and find ourselves facing a console with three screens: One shows a map of the city; another, an interface for checking license plates and addresses; and the third, the view from a gyro-stabilized L-3 Wescam camera attached to the chopper's nose. The camera can see clear across the city, in both the visible and the infrared slices of the spectrum; then it can broadcast the images to police headquarters using an onboard microwave transmitter.

The helicopter, part of New York City's antiterror arsenal, takes off and climbs to 1,000 feet in the afternoon sunshine. Passing the Verrazano-Narrows Bridge, Galligan scans for suspicious trucks lingering on approach ramps. Over the Staten Island Ferry, he explains how police routinely use the chopper to look for boats that might be trailing too closely. Then, as we swing past the gaping World Trade Center site, the 22-year veteran adjusts the joystick to turn the camera eastward, filling the third screen with the towers of lower Manhattan: the center of the center of the bull's-eye.

The New York Stock Exchange, the American Stock Exchange, the Federal Reserve Bank, City Hall, four major bridges and tunnels — a bomb at any of these places could kill hundreds, cost the city billions, and rattle the world financial system. Al Qaeda has hit lower Manhattan twice, in 1993 and 2001, and officials say that several other plots have been broken up since.

City agencies have done their best to harden the financial district in the years since 2001. Today, explosives-sniffing dogs and two truckloads of cops wearing military-style body armor and waving M-4 machine guns surround the flag-draped stock exchange. Black metallic barriers rise out of the asphalt, blocking traffic on Wall Street, while concrete planters and strategically parked trucks keep vehicles off Broad Street. Some of the other streets surrounding the exchange have been cut off to pedestrians, and only invited guests are allowed inside. "Closed since 9/11," the guard tells visitors.

But you can't block off every street or have a guard by every door. There's no budget for that, and no one would want to live or work in that kind of armed camp anyway. "You can make a justification for putting bollards in front of every building," says a former high-ranking NYPD counterterrorism official. "But pretty soon you can't walk anywhere. People leave."

So New York has an audacious blueprint to wrap a high tech cloak around lower Manhattan. It will provide the most sophisticated armor of any major urban area in the world — one that relies on brains as much as brawn, on barely visible technology as much as brute stopping power. And the chopper I'm in will be just a small piece of it.

Every so often, great cities have to remake themselves if they want to stay great — adding a new layer of technological infrastructure to meet the challenges of the day. In the 1880s, Thomas Edison built the first central electrical power plant in lower Manhattan. In 1904, the city finished its very first subway line. The 1980s saw new fiber-optic data pipes, and today New York is in the middle of its next major makeover. This time, the technological update is about keeping the city safe.

There will be upgrades citywide, including a new, next-gen cell network, an overhaul of the subway's security system, and an increase in manpower. But the financial district is a special case, and in June 2006 the NYPD announced a three-year, $106 million plan called the Lower Manhattan Security Initiative. Its centerpiece is an array of 3,000 cameras that will turn the area into a 1.7-square-mile, open-air Panopticon.

The first cameras started going in earlier this year. In contrast to London's surveillance system, the so-called Ring of Steel, New York's cameras will do more than identify terrorists after they've struck. The new cameras will be fully networked, with video-intelligence algorithms that aim to spot potential attackers before they perpetrate their crimes. Assistant chief John Colgan, who commands the police department's counterterrorism bureau, hopes the LMSI will keep the next disaster from happening. "This is about identifying and eliminating a threat, rather than dealing with the consequences," says Colgan, a compact redhead with a bushy mustache. "I'm not in the consequence-management business."

*Photo: Vincent Laforet * To support the plan, Colgan says, extra officers will be reassigned to downtown. Electronic license plate readers, both stationary and mounted on mobile police units, can already scan thousands of cars per day and instantly alert police if a suspect in their database approaches or enters the financial district. Massive vehicle barriers will be able to block off the busiest streets on a signal from HQ, even shutting down the Brooklyn-Battery Tunnel. Of course, the same technology could be used to invade privacy more efficiently, and even some in the NYPD are concerned: "I certainly don't want my family to come under view just because they're walking through a certain part of town," one counterterrorism official told me. And those questions become even more complex as Colgan brings the financial giants of lower Manhattan into the network: 2,000 of the 3,000 LMSI cameras will be privately owned, including 200 of the first 250, just installed.

The plan will also require builders of new skyscrapers, like the high-profile Goldman Sachs headquarters in Battery Park City and the Freedom Tower going up where the World Trade Center once stood, to submit blueprints to the city so police can ensure that security measures are part of the designs. (The Freedom Tower, for example, was moved farther away from the West Side Highway.) Colgan also wants those electronic blueprints on the network so they can be accessed easily during a crisis to help guide rescue efforts. Eventually, Colgan would like to be able to control just about every aspect of any new tower — the lights, the air-conditioning, the internal security cameras, the access controls — from a desktop at the new LMSI command center at 55 Broadway. The question is whether any amount of gear can stop a dedicated suicide bomber.

At 4:54 on the morning of July 7, 2005, Shehzad Tanweer entered a gas station about 200 miles north of London. As he was leaving, he looked into the lens of a security camera. At 7:21, another camera caught him and three other men walking into the train station in Luton. Tanweer shifted his backpack uneasily. An hour later, the four were recorded again, and at 8:50 a camera captured passengers boarding a train. Seconds after the doors closed, the bombs detonated. The blast killed eight, including Tanweer, and wounded 171.

London may be the most heavily surveilled city on the planet, with thousands of cameras in train stations, on street corners, and in parks, but this surveillance is useless against suicide bombers. Tanweer didn't care if he was caught on tape — he'd be dead before anyone reviewed the footage. Two weeks after the Luton bombing, cameras recorded another group of four as they brazenly tried to detonate more explosives on London's subways and buses. Fortunately, their weapons malfunctioned, and no one was killed. Again, the presence of electronic eyes did nothing to inhibit them.

That's because London has only a hodgepodge of partially connected cameras — some public, some private — not a fully integrated network. Monitoring them all is impossible, and security guards get little guidance about what to look for. But video surveillance technology has gotten a lot smarter since London's security was installed. New software can sound an alarm when it spots suspicious behavior — bags left on a platform, trucks circling, people entering a building through an exit.

Surveillance networks can now be taught even to recognize familiar faces. Technology from 3VR, a security firm in San Francisco that's funded partially by the CIA, makes it easy to sift through surveillance video. Click on a face and you'll see every instance in which that person has come within the field of view of a networked camera, allowing companies and government agencies to set up video watch lists. The system has already been used successfully to foil a check-cashing scheme.

British intelligence had followed Tanweer before, and tapes showed him and some fellow bombers rehearsing their plot several weeks prior to July 7. If the London cameras had been outfitted with the right software, his face might have triggered an alarm.

Dumb systems, no matter how extensive, don't seem to deter even small-time bombers. In early March, a bicyclist left a small homemade explosive at a military recruiting station in New York's Times Square, in plain view of more than a dozen security cameras. Weeks later, the bomber still remained at large, a perfect example of why the NYPD is turning to newer, networked video systems instead.

No one expects to catch a bomber in the act; this is real life, not 24. But with the right people and the right gear, it might — might — be possible to nab potential attackers while they're still casing their targets, when they're most vulnerable, Colgan says. If someone sneaks around the back of the New York Stock Exchange, say, or lingers too long in front of the Federal Reserve, the NYPD will know. "This is preventative," Colgan adds, "because we would expect those people who would attack us to be dead on the day they attack us."

Photo: Vincent LaforetNew York's counterterrorism overhaul is more than just a collection of shiny new gadgets. Under commissioner Ray Kelly, the NYPD has already put in place a combination of protective measures — some aggressive, others invisible. The police's intelligence unit used to be a trivial operation, just a handful of cops to protect VIPs. Today, it's a 500-person bureau headed by a former CIA director of operations, with so many Harvard-trained analysts that, at a party last October, more people were cheering the Red Sox than the Yankees. Plainclothes officers shadow terror suspects all over the city, and additional detectives are stationed overseas. Others work on Operation Nexus, reaching out to local and national businesses so they'll notify police when someone tries to make suspicious bulk purchases of, say, fertilizer or hydrogen peroxide. To show cops what to hunt for, the NYPD reportedly constructed a replica of the lab where Tanweer built his bombs. All told, more than 1,000 officers now work directly on counterterrorism, while the remaining 37,000 are drilled constantly on how to respond to the type of chaos caused by terrorist incidents.

But technological deficits still hold city agencies back. The 9/11 Commission famously criticized the city because Port Authority cops, who used a UHF radio system, and firefighters, who used weak radios that only other fire personnel carry, couldn't share information inside the towers. Though the police deny it was an issue that day, there's no question that emergency communications are far from perfect even now, seven years after the September 11 attacks.

Proof can be found in the emergency-management trailer, which I visited while it was parked next to City Hall. Inside, the trailer is lined with PCs and video screens, but Henry Jackson, deputy commissioner of New York's Office of Emergency Management, has to wear three cell phones on his belt, each from a different carrier, while several brands of radio hang on the wall. "You never know what's going to work, what coverage you're going to have," he says. Even relatively minor catastrophes — like when Yankees pitcher Cory Lidle crashed his plane into an Eastside apartment building — have snarled commercial voice and data traffic.

So the city is in the middle of a $500 million upgrade to create the NYCWiN (New York City Wireless Network), a speedy, 3G-on-steroids private data network solely for government data — one that won't get swamped in emergency situations.

Incident commanders could use it to pull images from surveillance choppers or data from license plate readers. Every ambulance and fire truck will be trackable on digital maps. And LMSI video feeds could be pumped directly to mobile command centers. Seventy percent of Manhattan should be online by this month.

In the trailer, Jackson's assistants click through video feeds streaming over a version of the new network. We see the Brooklyn Bridge, the Staten Island Ferry terminal, Canal Street. "Before, this was painfully slow," Jackson says. "Now, not so bad."

The plan to protect lower Manhattan sounds promising — on paper, at least. Colgan says he's confident it will work — though he refuses to demonstrate any of the new gear. "There are many elements to the initiative that we're not going to discuss publicly," he says. But, as the experience in other cities shows, all this new technology, once assembled, may not function as advertised.

In the summer of 2005, not long after Tanweer and his companions bombed the London Tube, the New York subway system signed a deal with defense contractor Lockheed Martin to put in security cameras, motion sensors, perimeter sensors, and intelligent video. So far, only three out of 16 components are in place. The problem is wedging a modern security network into a 100-year-old system. Just getting the power and air-conditioning needed for the cameras' servers has been a nightmare; in many stations, there's literally no place to put the things. Plus, the ceilings in most of the subway stations are only 9 feet high, with columns every few yards. That makes it hard to get a good look at passengers. Add a sprawling bureaucracy — the Metropolitan Transportation Authority is really a combination of seven agencies — and costs are going to multiply. Not surprisingly, the security upgrades, which are not even part of the LMSI, are already 70 percent overbudget and 15 months behind schedule.

Of course, the LMSI doesn't have to deal with the logistical nightmare of operating entirely underground. But it also doesn't have the advantage of operating in a confined, well-lit space like a bank or a casino — the only places where video intelligence has worked in the past. And no one has ever tried to create a system as big as the LMSI. Even police commissioner Kelly doesn't sound completely convinced. "We've got an eye toward prevention," he says. "I like cameras because they act as a deterrent." In other words, maybe the new video system doesn't even have to work as advertised in order to have the desired effect. Maybe the goal here is a kind of digital placebo effect: Just say that the cameras are all linked up.

"The cameras become a great subject for conversation because they'll all be in public areas," Colgan says. "And quite frankly, we want people to see them." In London, terrorists were undeterred by a system they knew was passive and dumb, but in New York they may think twice if they believe they are going up against a smart network.

"A big part of security is psychological warfare," says RAND specialist Brian Jenkins. A terrorist is going to successfully attack New York again. Everyone knows that. The point is to make sure it's not a knockout blow. And that means introducing a little fear into the mind of the attacker. "Look, a stick of dynamite in a briefcase — there's not a lot you can do. But that's not going to bring the financial district low," Jenkins says. "You've got to make the threshold for a successful attack as high as possible," he says. "Hound them. Make it hard for them to do their surveillance. Deter them as much as possible. Harden your sites so their attacks won't be as effective. And make it clear that if they haven't blown themselves up along the way, you're going to catch them. With that combination of measures, that's about as good as it gets."

Flying at 1,000 feet, Brendan Galligan and I dart up Manhattan's West Side — over the docks, past midtown and Central Park. We soar over the Bronx and look down on Yankee Stadium. Then, at the northern end of the city, he spins the camera back to Brooklyn. On the screen, we can clearly see the radar ball at our heliport some 25 miles away. "Awesome, right?" he says, smiling. From the air, when everything looks so calm, it's easy to forget all the times the city has been targeted — and how much work goes into keeping the peace. We circle back to Brooklyn, and the chopper lowers daintily onto the helipad at Dead Horse Bay.

Contributing editor Noah Shachtman (blog.wired.com/defense) writes about military robots in this issue.

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