Story highlights Elana Broitman: New Yorkers' response to Tribeca attack highlights how urban communities across the world use the connective tissue they build over time to heal

As NYC prepares for the celebrated tradition -- the marathon -- diverse communities will greet complete strangers as they cheer the runners, she writes

Elana Broitman is the director of New America NYC. Formerly, she was a senior adviser on national security to Sen. Kirsten Gillibrand and deputy assistant secretary in the Office of Manufacturing & Industrial Base Policy in the Department of Defense. The views expressed in this commentary are solely those of the author.

(CNN) As Sen. Kirsten Gillibrand's senior adviser for national security, I spent a lot of time getting to know the vigilant, behind-the-scenes-work of the New York City Police Department to keep New Yorkers safe from planned terrorist attacks.

Mothers and fathers raising families in New York City see NYPD efforts first hand -- but also see the strength and resilience of everyday New Yorkers that flies in the face of those who would frighten us. This human resilience comes, in large part, from living and working together in urban environments. Neighbors constantly interact in apartment buildings and say hello to small shop owners while running errands, parents rub shoulders with other parents on the playground, and commuters recognize and smile at familiar faces on their bus routes.

Elana Broitman

Over time, those small interactions build up into a connective tissue that binds us together. This week, in the wake of the terrorist incident in Tribeca, New Yorkers witnessed this connective tissue at work.

Neighbors and acquaintances who know each other simply because they drop their kids off at the same school buses quickly turned to each other to alert family and friends, offer to pick up kids stuck at school and generally offer emotional support. Friends texted and called each other to check if everyone was safe, and to see whether anyone needed a hand. Parents told their children: Don't be scared, be aware of your surroundings, but focus on the network of support we rely on as New Yorkers. And kids and adults alike turned out for Halloween trick-or-treating, even downtown -- not to mention the Halloween parade.

"To change plans would be unacceptable," said one New York resident , a sentiment echoed by the mayor and governor alike.

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