Iraq Implodes: What You Need to Know

An al-Qaeda-inspired group that captured two key cities in Iraq this week vowed this week to march on to Baghdad, raising fears about the government's ability to slow the assault, following the insurgents' lightning gains. Fighters from the militant group known as the Islamic State in Iraq and the Levant (ISIL, or sometimes called ISIS) took former Iraqi president Saddam Hussein's hometown of Tikrit on Wednesday, as soldiers and security forces abandoned their posts and yielded ground once controlled by U.S. troops.