In August 2014, the United States and its coalition partners began an air campaign against Islamic State of Iraq and the Levant (ISIL) in Iraq and Syria.
The armed group's rapid rise and expansion have made the five-year war in Syria that much more complicated.
There have been victories and defeats along the way for all involved, but what is clear is that ISIL, also known as ISIS, is still a powerful opponent.
The US-led coalition says it has launched nearly 15,000 strikes against the armed group since it began its campaign.
And it says the coalition has significantly diminished ISIL's territory since then.
But watchdog groups say the air strikes have also killed hundreds of civilians.
And have largely failed to stop the expansion of ISIL within Iraq and Syria.
So, what does it take to defeat ISIL?
Presenter: Richelle Carey
Mouyad Al Windawi - Fellow at the Iraqi Centre for Strategic Studies.
Hardin Lang - Senior Fellow at the Center for American Progress.
Matthew Glanville - Former British Army soldier and adviser to the Iraqi, Afghan and US governments.
Source: Al Jazeera