他已经下到安全的楼层了，然后他转身又上去了：二十五年后，「红头巾的人」拿到了总统自由勋章

Start with an object: a red bandana.

That bandana is now a museum piece, and a symbol.

This episode is about how it became one.

Last week, the United States awarded the Presidential Medal of Freedom to a man who died twenty-five years ago.

It is the highest honour America gives a civilian.

His family collected it.

Now the man.

Welles Crowther graduated from Boston College in 1999, where he played lacrosse.

In 2001 he was twenty-four, working as an equities trader for an investment bank in New York.

His office was on the 104th floor of the South Tower of the World Trade Center.

He had one habit he had kept since childhood.

When he was six, his father gave him a red bandana.

He carried it from then on — tucked into his jersey when he played, in his suit pocket once he was working.

There is one more thing, and it bears directly on what follows.

From the age of sixteen he served alongside his father as a volunteer firefighter in his home town.

Volunteer firefighters are unpaid; they have their own day jobs and turn out when something happens.

Which is to say: he had been trained, and he knew how to move through heavy smoke.

On the morning of 11 September, the second plane struck the South Tower between floors 77 and 85.

He was on the 104th floor — above the impact.

Of all the stairwells above the impact point, only one was still passable, and at the time almost nobody knew which.

He called his mother and left a message.

Then he made his way down to the 78th-floor sky lobby.

That floor was the worst of it: people above could not get down, people on that floor did not know which way to go, and there was smoke and debris everywhere.

He took out that red bandana and tied it over his face — the smoke was so thick you could not breathe without covering up.

Then he did something very specific: he started shouting, telling everyone which stairwell was open.

He led from the front and took a group of people down.

Once he reached a safe floor, he did not keep going down.

He turned round and went back up.

There were still people up there.

He did this more than once.

On one of those trips he carried a woman who could not walk down seventeen floors, handed her to people below, and went back up again.

On the 78th floor he also helped fight fires and gave first aid to the injured.

The last time anyone saw him, he was with several New York firefighters, heading upward.

At 9:59 that morning, the South Tower collapsed.

He did not come out.

What follows is the most unusual part of this story.

For a long time, nobody knew who he was.

Survivors kept describing the same person: a young man with something red over his face, shouting in the smoke for everyone to take a particular stairwell.

Nobody knew his name. They could only call him "the man in the red bandana".

In May 2002, a survivor told the story in the New York Times.

His mother read that piece.

At the words "red bandana", she recognised her son.

Earlier than that, in March 2002, his body had been found in the South Tower lobby, alongside several firefighters.

Based on the survivor accounts we have, he helped about eighteen people that day.

All eighteen walked out of that building alive.

Since 2014, Boston College has held an annual "Red Bandana Game" where the whole crowd wears red.

Here is the point I want to make.

Leading people down the first time took courage.

But the first time is not the hard part.

He had already reached a safe floor. He already knew the exit was below him.

Turning round from that position takes something else.

And he turned round more than once.

Think about it:

You are already down. You are already safe.

There are still people up there, and you know it.

Would you go back up?