FALLUJA

Fallujah was captured by Isis in January 2014 and recaptured by the Iraqi military in June 2016.

The restive Sunni-dominated city was the first to fall to Isis and has been an important incubator for Sunni extremism.

The Iraqi effort to retake Fallujah left it less devastated than Ramadi. Even so, weeks of indiscriminate shelling by Shia militias, as well as fierce fighting in the final weeks of the assault, left sections of the city in rubble.

Before Iraqi forces proclaimed victory in June, officials estimated that 90,000 civilians were in Fallujah; the city’s population at its height was close to 300,000. Lisa Grande, the top UN humanitarian aid coordinator in Iraq, said more than 70,000 had since returned.

Once recaptured, Mosul could pose a far more complicated rebuilding challenge, given that it is so much bigger than other Isis conquests and was much more diverse, with Christian, Kurdish and Shia minorities.

“The big difference between Mosul and the cities of Ramadi and Fallujah is the size of the city,” Ms Grande said.