The Secret History of ISIS documentary. PBS presents the history behind the radicals who became the infamous militant group ISIS. The fuel behind the group largely came to be because of the Invasion of Iraq and decisions made by a number of US presidents. In the documentary we see how Abu Musab al-Zarqawi, a one-time thug turned jihadi leader, was able to outmaneuver the U.S government and create one of the most feared organizations of all time. It started in the middle east but its influence has spread around the world.