For Muslims around the world, observing the holy month of Ramadan is about prayer and finding peace, but for ISIS it is a period of bloodshed and destruction.
ISIS has claimed that the al-Nuri Great Mosque was destroyed by a US airstrike. But footage from Iraqi forces is indisputable. The jihadi group has undoubtedly used explosives to destroy the ancient and revered religious site on one of the holiest days in the Islamic calendar, the Night of Power, when Muslims celebrate the revelation of the Quran to the Prophet Muhammad.
Over time, ISIS has destroyed numerous historical sites. This has always been justified by reference to eradicating any form of polytheism or association with God, interpreted through a militant lens. The group proclaimed that detonation of shrines, Shia mosques, and pre-Islamic sites were not acts of mindless vandalism, but rather a religious obligation.
But the al-Nuri Mosque is different. That narrative has crumbled. This atrocity is guided by tactical considerations, rather than ideological zeal. The mosque was the site of Abu Bakr al-Baghdadi's speech in June 2014, in which he proclaimed himself 'Caliph,' and spoke about the obligation on Muslims to migrate to, and fight for, the new 'Islamic State.' Declaring, during the month of Ramadan, that the marketplace of jihad is open. Saying that fighting ISIS' vision of jihad was incumbent upon Muslims in the same way fasting was.
Destroying the very place ISIS' caliphate began appears to be a final, desperate act by the jihadis to deny Iraqis the ability to win back their ancient heritage. Seemingly prepared to do anything to avoid giving those fighting ISIS the opportunity to proclaim a moral victory over the group.
Commanders on Sunday announced the start of the "final chapter" of the offensive on ISIS' Iraqi stronghold. After a bloody nine month offensive led by Iraqi forces, Shia militias, Kurdish Peshmerga, and Sunni Arab tribesmen, Mosul's Old City is the only district of the group's de facto Iraqi capital remaining in ISIS' hands. The full recapture of Mosul would leave pockets of control west and south of the city, but would in essence indicate ISIS' loss of the Iraqi territory.
Haider al-Abadi, the Iraqi Prime Minister, described ISIS' destruction of the al-Nuri mosque as "a formal declaration of defeat" by the group. But to what extent does this constitute a metaphor for the group's imminent demise?
With efforts gaining momentum to oust the group from its de-facto Syrian capital, Raqqa, there is a perception that the fight against ISIS is reaching its conclusion. But while buildings that once housed militants may be crumbling and territorial in Iraq and Syria falling, the poisonous ideology of the group has spread far and wide - inspiring jihadis beyond the confines of the Middle East.
In the month of Ramadan alone, ISIS has claimed responsibility for 13 attacks in 10 countries killing at least 128 people, with notable attacks in the UK, Iran, alongside a large-scale insurgency in the southern Philippines.
Question marks remain about how authentic ISIS' claims of responsibility actually are, but nevertheless it is clear that individuals and networks that are not territorial connected or in direct communication with ISIS have the desire to commit atrocities around the world.
ISIS have revolutionised the way jihadi groups use digital media. The group has demonstrated its ability to produce and circulate slick pieces of propaganda in multiple languages. The use of encrypted messaging applications has helped likeminded jihadis from different parts of the world communicate with each other, giving them the ability to stay connected to ISIS' network of 'information' outlets.
When the dust eventually settles in Mosul and Raqqa, once the last militants have been driven out of their foxholes, there will rightly be an inevitable sense of accomplishment.
But the fight against global jihadism is fundamentally a battle of ideas, one that despite our best efforts cannot be won solely on the battlefield. Engaging and dismantling the appeal of this ideology must be the international communities number one priority.