On September the 11th, 2001, terrorists hijacked four American commercial jets with the intention of crashing them into large, visible buildings in both Washington, D.C., and New York City. As we all know, the terrorists were successful in three of the four cases; the fourth plane’s assault on the United States Capitol — the presumed target — was thwarted by the heroic passengers on board. While we now believe that no other planes were targeted, at the time, each of the other 4,000-plus flights scheduled to be in American air space at the time were at risk. But Ben Sliney, the Federal Aviation Commission’s National Operations Manager on duty that morning, prevented future harm.

How? He made an unprecedented decision, making the call to ground every single commercial airplane in the country.

That, of course, is not news — in fact, it’s rather common knowledge. While hindsight teaches us that the call was correct, at the time, it was a rather aggressive decision. Thankfully, it was the type of decision which Sliney was well-equipped to make. He had 25 years of experience in air traffic control and/or as part of FAA management, including a leadership position at New York TRACON, which has responsibility over the air traffic for New York City’s three major airports and a few smaller regional airports nearby. His position as National Operations Manager gave him immediate access to information as it became available. But the decision to ground the planes — that was Sliney’s to consider, and ultimately, to make.

In all, Ben Sliney’s initiative makes for an incredible story. When Universal Pictures decided to turn the heroism of the passengers of United Flight 93 into a movie, they did not overlook Ben Sliney’s role — they even asked him to play himself in the movie, as seen below.

But as incredible as his story is, one particular fact makes it jaw-dropping: on September 10, 2001, Ben Sliney was not yet a National Operations Manager for the FAA. September 11, 2001, was Ben Sliney’s first day on the job.

Bonus fact : During the three-day ban on commercial flights, very few planes were in the sky — by and large, air traffic was limited to military flights. (One exception? A San Diego to Miami flight, authorized to take flight in order to deliver antivenin to a snake bite victim.) Because of the lack of planes, there was also a lack of contrails, those white cloud-like tracks planes leave in the sky. The lack of contrails corresponded to a measurable, significant increase in temperature, leading some to believe that contrails help depress global warming — a theory echoed by World War II data as well.

Related: “A Place of Remembrance: Official Book of the National September 11 Memorial” by Allison Blais and Lynn Rasic, with forward by Michael Bloomberg, Mayor of New York City. Five stars on three reviews.