Hey, I'm Kelly McEvers, and this is embedded.

In 2010, a guy set himself on fire in Tunisia and eventually died.

People went out into the streets and demanded that the dictator of Tunisia had to go.

And soon millions of people across the Middle East were doing the same thing, including

In Syria.

You might not remember this, but the war in Syria actually started as a protest.

Pretty soon though, government forces started shooting protesters and people started fighting

back.

That's when it became a civil war, government versus anti-government.

But then it became something else.

I covered Syria back then, and to go there, we would have to sneak over the border from

Turkey.

And at one point, we started to see these other guys crossing the border too.

Guys with long beards and short pants carrying gun-sized boxes.

Guys who would say they were doctors, but looked like something else.

Guys from the Gulf, the former Soviet Union, Europe, Northern Africa.

And the Turks wanted to let these guys into Syria, so they could help fight against

the Syrian government.

They didn't know what none of us knew.

Was that eventually some of these guys who came over the border would have other goals.

Like fighting not just the Syrian government, but anyone who stood in the way of their

ultimate goal.

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