Before we begin, a warning that this program contains some discussion of events that may cause distress.

Being an informed citizen is not always easy.

You want to know what's going on, to stay up to date with the big news stories that affect your fellow humans across the planet.

But the non-stop headlines makes it difficult to completely understand what's happening.

This is where we hope the explanation from the BBC World Service can help.

I'm Anu Anand and in this series I ask some of my BBC colleagues to help me break down big global news events, using archive recordings made on the ground to make sense of why these stories are important.

Raka and Syria, it's a city where mothers carry guns along with their groceries.

Today we look at IS and ask how the Islamic State group has morphed from a brutal caliphate to a scattered movement that may yet threaten global security.

This is the explanation from the BBC World Service.

The BBC's Quentin Somerville is based in Beirut, Lebanon.

He's reported from nearby Iraq and Syria during the emergence, the rise and fall of the Islamic State group.

In Syria it takes a lot of confidence to replace your windows.

But the damage done here isn't just to buildings. And at the ruins this was an IS headquarters.

You find reminders of the victims. They disappeared, the lost and the dead.

So Quentin, what has been the impact of Islamic State on our modern world?

It's a group that emerged from the shadows. It attacked our communities across the world. It's based was the Middle East, but it was able to reach into communities.

And not only that, some of our own people were a part of this enormous global terror machine, which really changed the way that the West and countries in the Middle East fought wars.

Before the US war on terror, no one had heard of the Islamic State group, also referred to as ISIS, ISIL or just IS.

But in 2003, partly in response to the attacks carried out by Al Qaeda in the US in 2001, President George W. Bush invaded Iraq.

What happens once the US goes into Iraq? What is going on that gives rise to this idea of Islamic State?

One of the most striking things about Iraq, even under Saddam Hussein, who of course was a notorious dictator, was Iraq. It was a very developed country, I think at the time.

And the United States went in there to, as it described, liberate the Iraqi people from that dictator. And in the process of doing that, it busts a sunder Iraqi society.

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