A tank of the Emergency Response Division fires at
Islamic State militants in the old city of Mosul.
Photo by Alaa Al-Marjani/Reuters
Last October, Western-backed Iraqi forces began to re-take Mosul, Iraq's second largest city, from the occupying Islamic State. One hundred thousand troops have been involved — 10 times more than ISIS militants — but it's still taken eight months and the battle isn't completely over. Ben Watson is news editor for Defense One, which has an extensive account of the world's largest military operation in nearly 15 years.