5. Bulldozing the Border Between Iraq and Syria

On August 8, nearly three years after the United States pulled out of Iraq, President Barack Obama ordered airstrikes to commence on Islamic State positions in northern Iraq, as the group’s fighters advanced towards the Kurdish capital of Erbil. For six weeks prior to the strikes the Islamic State made stunning gains within Iraq, effectively dismantling the border with Syria and defeating the Iraqi army with little in the way to stop them.