According to French President François Hollande, the terrorist attacks in Paris —which claimed more than 120 lives — were the work of the Islamic State, better known as ISIS. The group rose to prominence in June 2014, when it seized Mosul, Iraq's second largest city.
But to understand the militant group, you have to understand where it came from — a story that really starts in the aftermath of America's invasion of Iraq. The above video explains.
