Keeping NYC safe in a post-9/11 world

Nearly seven years after terrorists took down the World Trade Center's twin towers, police officials have embarked on an ambitious plan to secure the new development that is finally sprouting at ground zero.

But a repeat of the horrors of Sept. 11, 2001 is only one of a long list of worries that have prompted the New York Police Department to spend the last several years reinventing itself as an intelligence and homeland security agency.

The nation's largest police department, with about 37,000 officers, has spent tens of millions of dollars -- much it from federal grants -- on an array of high-tech security measures designed to thwart threats potentially more daunting than another attack on a downtown skyscraper. It's also assigned 1,000 officers to counterterrorism duty, including 10 detectives posted around the globe who collect and share intelligence.

Overall, it's an effort unmatched by any other city in the nation, and perhaps the world.

9/11 lessons profoundly change NYPD

David Cohen -- a former CIA official brought aboard after Sept. 11 to head the NYPD's intelligence division -- said the department has identified more than a dozen serious plots against the city in the past seven years that were either interrupted or abandoned, including some that haven't become public.

For terrorists, attacking New York City "is marbled into their thought process," Cohen said. "If you want to get into the major leagues in the terrorism business, you come here." Cohen and Richard Falkenrath, the department's counterterrorism chief, drive home that point in daily briefings with Kelly.