This TED Talk features activist Jill Hicks recorded live at TEDx Sydney, 2016.

I could never have imagined that a 19-year-old suicide bomber would actually teach me a valuable lesson.

But he did. He taught me to never presume anything about anyone you don't know.

On a Thursday morning in July 2005, the bomber and I, unknowingly, boarded the same train

carriage at the same time, standing apparently just feet apart.

I didn't see him.

Actually, I didn't see anyone. You know not to look at anyone in the tube, but I guess he saw me.

I guess he looked at all of us as his hand hovered over the detonation switch.

I've often wondered, what was he thinking,

especially in those final seconds.

I know it wasn't personal.

He didn't set out to kill or maim me, Jill Hicks. I mean, he didn't know me.

No.

Instead, he gave me an unwarranted and an unwanted label.

I had become the enemy.

To him, I was the other, the them, the them as opposed to us.

The label enemy allowed him to dehumanize us.

It allowed him to push that button, and he wasn't selective.

26 precious lives were taken in my carriage alone, and I was almost one of them.

In the time it takes to draw a breath,

we were plunged into a darkness so immense

that it was almost tangible.

...