Mosul's Old City threatened as showdown looms

Mosul's Old City, where Iraqi forces are closing in on the Islamic State group's final urban refuge in Iraq, is an ancient maze of narrow alleys.At its heart lies the emblematic Al-Nuri mosque, where jihadist supremo Abu Bakr al-Baghdadi declared a caliphate in June 2014 after his forces seized Iraq's second city along with swathes of territory extending into neighbouring Syria.