Hello and welcome to the History Hour Podcast from the BBC World Service with me Max Pearson, the past brought to life by those who were there.

This week, the biggest machine in the world, the Large Hadron Collider, and why it went wrong just after it was switched on?

There are about 30,000 high precision welded connections.

One of these connections was not made properly.

Plus from the 1980s, the death of one of Spain's most celebrated bullfighters,

the birth of the Sound of Music on Broadway in 1959 and the extraordinary story of of grass skirts of course. Sometimes I even had to go to school in a grass skirt.

That's coming up later in the podcast, but we begin by going back just a few years to a period in

modern history which for a time appeared to take parts of the Middle East back to the Middle

Ages certainly in respect of the punishment of perceived transgressors.

In 2014 the Islamic State Group, I.S. occupied Mosel in northern Iraq.

They recorded their reign of terror in propaganda films broadcast on the internet, but one historian living in M, was posting a counter narrative in what became

a clandestine battle online.

Rebecca Kesby reports.

ISIS is a grouping of some of the world's most violent militants, so extreme they've been disowned by Al-Qaeda.

Bloody chaos in Iraq, large swathes of territory are in the militants' grip.

With their black flags flying, long convoys of Islamic State fighters swept across

northern Iraq with terrifying speed,ily armed and utterly merciless, they took Iraq's second

city, Mosul, in less than a week. Claiming a radical Salafist theology, the Islamic State

Group or IS

wanted to impose strict religious law.

For locals who'd already experienced years of conflict,

this was a new terror.

...