Islamic State group fighters are losing large numbers of men along with their grip on Mosul, the Iraqi city they once completely controlled. The battle is now centered on the Great Mosque of Al Nuri, in Mosul’s Old Town, where ISIS fighters are making a ferocious last stand.

The mosque is a symbolic site for the terror group. It’s where their leader, Abu Bakr al-Baghdadi, made his only known public appearance, in July 2014, to announce the creation of an Islamic caliphate.

According to the top U.S. commander in Iraq, the battle for Western Mosul is the most brutal urban combat since World War II.

VICE News’ Seb Walker is on the ground with soldiers from the third division of Iraq’s Federal Police to find out what it’s like living on the front line of Mosul.