One day before the Friday terrorist bombing of a London Underground train, a group of former top Mossad and IDF officials and terrorism experts played out an even scarier possible scenario: an ISIS attack on the Vatican.Playing roles for the IDC Herzliya International Institute for Counter-Terrorism conference, panelists simulated a meeting of ISIS’s core leadership trying to plot a mega-terrorist attack in order to stay relevant while it loses its foothold in Syria.Playing for maximum effect, ICT founder and Government School dean Boaz Ganor stood in as ISIS leader Abu Bakr al-Baghdadi, loudly egging on his military council for a game-changing attack.Former deputy Mossad chief Naftali Granot played the part of the head of ISIS’s military council.“Over the last six years... we have suffered military defeats,” he said. “But this is definitely not the end... We will focus now on mainly what we are more capable of: inflicting damage on the infidels in various countries using suicide and other terror operations. We have lots of advantages as silent attackers.It will be much easier for us than fighting a military land campaign. This new stage will be a full long terror campaign.”Granot then suggested that ISIS should direct most of its foreign fighters in Europe back to their countries of origin where they would be well-positioned to carry out terrorist attacks. “We have managed to smuggle lots of arms, explosives and ammunition to a variety of locations in Europe, and they are merely waiting for your order to start a full-blown campaign of terror,” he said in a chilling simulation of ISIS’s top military official.Providing a list of potential targets for the ISIS caliph to choose from, ICT fellow and former IDF Lt.-Col. Uri Ben Yaakov acted as ISIS’s intelligence chief, darkly listing off England, France, Italy and the Vatican.Showing how unfortunately unsurprising Friday’s attack in London was, Ben Yaakov presented ISIS as possibly having as many as 1,250 returned followers and that the group’s past “successes” in Britain included killing 200 civilians in a single strike.He cautioned that London was not the easiest target because Britain is not part of the Schengen Agreement that allows easier movement between certain European countries.After detailing why France was another strong target for ISIS, Ben Yaakov honed in on the best target: Italy, and more specifically, the Vatican.Such an attack would have “great symbolic value since it is the symbol for Christianity,” he said.Granot supported this attack idea, saying that England and France had been improving their security practices after many terrorist attacks, whereas Italy was still “far more loose since it had been spared” the same level of attacks.Continuing his role as ISIS’s military leader, Granot said all of this made “the chance of surprise much better” and that they should explore “carrying out a suicide mission on a Sunday during mass, with maybe a chance to” get “the pope himself.” At this point Ben Yaakov tried to redirect the debate from an attack on the Vatican and the pope to an attack on the Rome Marathon or one of a few of Italy’s train stations with close proximity to the Vatican.Arguing that these were easier targets than the more highly- guarded Vatican, he detailed which train stations had metal detectors, bomb-sniffing dogs and other more hi-tech security and which did not.The ISIS performers even got into operational details, discussing specific numbers of suicide bombers and the use of a particular drone that can be purchased on Amazon for only $700.They spoke about the types of materials which can be easily acquired to make homemade explosives and how to rent a location near the attack, timing the distances that different parts of the terrorist cell would need to traverse.The meeting was topped off by former IDF Lt.-Col. Eyal Dykan playing the leader of ISIS’s Shura Council and ICT deputy director Eitan Azani in the part of its chief of propaganda.