- The group's atrocities have angered Americans, Jordanians and Egyptians
- Bergen: ISIS actions only make sense if you realize that its aim is the apocalypse.
Peter Bergen is CNN's national security analyst, a vice president at the New America Foundation and the author of "Manhunt: The Ten-Year Search for bin Laden -- From 9/11 to Abbottabad."
(CNN)Whenever ISIS carries out a new atrocity, whether it's beheading a group of Egyptian Christians or enslaving Yazidi women in Iraq or burning its victims alive, the big question most people have is: Why on Earth is ISIS doing this? What could possibly be the point?