There are heroes in the making and heroes of the moment. In the terrorist attacks on Tuesday, there is unspeakable sadness in the knowledge far too many people were thrust into those roles - and died for little more reason than they were in the wrong place at the wrong time.
Amid all the shocking carnage that accompanied the attacks in New York and Washington, it was stunning to learn that perhaps 200 firefighters and police officers were killed at or near the World Trade Center.
These are heroes whose job is to run toward danger, when everyone else is running away. Every day, they know, could be the day they will be called upon to enter the inferno. Tuesday was that day.
The timing could not have been worse for rescue personnel, who were rushing to the scene of a burning, exploding building - only to have a second airliner crash and unleash whatever fury hell had left.
The death of even one firefighter, or one police officer, is enough to throw a community into mourning. We have seen such losses. We have never seen anything like Tuesday's disaster.
Someday, we may be able to comprehend the magnitude of those losses. For now, we can only begin to replace the numbness with prayer and sympathy.
Heroes of the moment, it appears, were present in the airliner that ended up crashing in rural Pennsylvania.
A telephone call by Tom Burnett, 38, to his wife while the plane was being hijacked contained these chilling words: "We're all going to die, but three of us are going to do something."
The speculation is that passengers somehow were able to thwart the hijackers' plans to crash the jet into yet another target. If that's what happened, the passengers may have saved hundreds of lives, even as they lost their own.
Sorting through the wreckage of Tuesday's events, each of us wonders how we would have responded had we been in their shoes. If we're lucky, we'll never have to confront that moment.
But know that, in America, someone will step up to do what needs to be done.