Displaced people from the Yazidi religious minority walk from Mount Sinjar towards the Syrian border (11 August 2014)
Media playback is unsupported on your device
Video

Islamic State crisis: The struggle for Mount Sinjar

Kurdish Peshmerga forces in northern Iraq are claiming their biggest victory yet against Islamic State (IS) militants.

They say they have broken the siege of Mount Sinjar, where tens of thousands of members of the Yazidi religious minority were trapped in August.

The BBC explains the area's significance - in 90 seconds.

Video produced by Michael Hirst

Go to next video: Kurds: 'Biggest victory yet' over IS