>> when the u.s. invaded, it hadn't really thought much about the day after. it was very much focused on overthrowing saddam. >> there it goes. there it goes. >> and what happened in the initial weeks was a total power vacuum. >> as the american occupation quickly devolved into chaos, one man seized the moment. that man is abu musab al zarqawi, the godfather of isis. in 2004 zarqawi swore allegiance to osama bin laden and became the leader of al qaeda in iraq. >> the u.shas described him as one of the world's most dangerous terrorists. >> zarqawi's ultimate goal was to create an islamic state. and events in iraq were going to give him the chance to realize his dream.