Militants of Islamic State (IS) parade at somewhere in Syria. Photo: cfr.org

Militants of Islamic State (IS) parade at somewhere in Syria. Photo: cfr.org

Islamic State (IS) shocked the world when they took control of Mosul, Iraq's second city, in June of this year.

Looting from banks and military installations in the town gave a significant boost to the group's assets - supplementing income from ransom payments and oil fields in both Iraq and Syria

IS is now the world's richest terror group, with wealth estimated to be in excess of $2billion.

The group emerged from Syria's ongoing civil war - having fought alongside other rebel groups, including those with jihadist affiliations.

Their de facto capital is the Syrian city of Raqqa - which they seized this year following months of fighting.

Western hostages are believed to be held in a network of tunnels surrounding the city, with little reliable information emerging from the IS stronghold.

Their advance into Kobane puts them on the doorstep of Turkey - who like the US and the UK are part of Nato.

If IS were to advance any further, Western powers would be required to intervene under Article 5 of the organisation's treaty.

The US are also intent on making sure that IS do not take Baghdad, Iraq's capital city.

Watch the video to see how IS took various cities in both Iraq and Syria under their control - despite resistance from local fighters and intervention from Western air forces.

By Jon Laurence, The Telegraph