Ok. I bet most of you know this already, but there's 10 000 every day, so here I go.
Iran is a country based on a strict adherence to Shia Islam. While many people are secular, the roots of Shia Islam go back to the early days following the death of the prophet Mohammed. Long story short, there was a succession struggle, and Husayn, who was Mohammed's grandson lost and was killed by the corrupt Umayad dynasty. Those who supported Husayn became the Shia, and branched off from Sunni Islam. The fundamental idea in Shia Islam (aside from the prophet and the Quran) is the example of Husayn, who rather than surrendering when outmanned 72 to 4000, chose to fight for truth and justice, and dying for it. His martyrdom created shi'ism.
They celebrate/remember his martyrdom in a 10 day long festival every year. I'm not sure if intimidation is gonna work on these guys.