With Tuesday's seizure of Mosul, Iraq's second largest city, the Islamic State of Iraq and Syria notched a major victory in its campaign to create a new country containing parts of what had part of both Syria and Iraq. On Wednesday, the insurgents continued their march south, taking control of Tikrit, the hometown of Saddam Hussein.
The story of ISIS's spread -- and its influence -- is one that begins in Syria, where the group has been waging a brutal insurgency against the regime of Bashar al-Assad and, increasingly, other more moderate and secular rebel groups. The map above depicts the areas of Syria under its control. The group's influence is bounded by the Free Syrian Army in the west, the Kurds in the north, and pockets of government influence. Who is the ISIS/ISIL?