This segment originally aired Oct. 17, 2016, on VICE News Tonight on HBOMore than two years ago, fighters from the Islamic State group overran Mosul, one of Iraq’s largest cities. It became the jihadi group’s de facto capital in Iraq, and it’s a key transport hub between Iraq and Syria and controls a major oil pipeline to Turkey.On Oct. 16, a Western-backed coalition of 30,000 troops launched the fight to take the city back. It was the first time Kurdish peshmerga soldiers and the Iraqi Army have worked side by side. U.S. Secretary of Defense Ash Carter called the offensive a “decisive moment” in the war to defeat IS.Spokesmen for the allied forces said on Oct. 17 that they’d inflicted “heavy losses of life and equipment” and liberated several villages on the way to the city itself.But the campaign could take months, and the long-term outcome is far from certain. VICE News correspondent Aris Roussinos was with Kurdish peshmerga troops as they began their push toward Mosul.