Yazidis in northern Iraq and around the world, as well as other victims of ISIS, mourned the anniversary of the jihadist group's attack on Sinjar five years ago this week. In addition, a separate attack on August 15, 2007, among the world's worst terror attacks in decades, is remembered for killing more than 800 Yazidi people. That attack, likely by jihadists linked to Al-Qaeda in Iraq, is now seen as a prelude to the genocide that ISIS carried out in 2014.Yazidi social media accounts have been tweeting images from the 2007 and 2014 attacks, with some sharing memories of the horrific experiences. Mumtaz Ibrahm wrote that the 2007 attack was one of the “fiercest and dirtiest” in modern history. A Twitter account called @Daeshcrimes put up video from August 2014 showing ISIS taking over areas in Sinjar, in northern Iraq. While the 2007 attack on the villages of Siba Sheikh Khidir and Qahtaniyah was by car bombings and destroyed up to 600 homes, the 2014 genocide was carried out after ISIS fighters overran the area of Sinjar city and the mountain with the same name. Called Shingal in Kurdish, the area is home to hundreds of thousands of the ancient Yazidi minority. In 2007, Al Qaeda and its allies began to perfect their technique of using massive truck and car bombings against religious minorities. They targeted members of the Kakeye minority near Kirkuk, struck at Shebeks and Kurds, and attacked Shi’ites in a campaign that stretched for years from 2005 to 2009. ISIS grew out of the extremism of those years, borrowing from the ideology and perfecting it, much as Nazism grew from its fascist origins into its genocidal maturity in the late 1930s.In June 2014, ISIS conquered Mosul and areas in Iraq's Nineveh plains. It proclaimed a “caliphate” and committed mass murder against Shi’ites, executing 1,500 men at Camp Speicher. It expelled Christians and then set its sights on attacking Sinjar. In a surprise attack that August, it overran numerous Yazidi villages. Hundreds of thousands of Yazidis fled to the mountain and then, via a corridor carved out by Kurdish People’s Protection Units fighters from Syria, they were able to escape. However, more than 10,000 who were captured by ISIS were sold into slavery or executed and buried in more than 30 mass graves. ISIS members bragged on social media and celebrated their acts openly.Murad Ismael, a Yazidi activist with Yazda, wrote that “humanity collapsed” on August 15, 2014 when 1,700 Yazidis in just one village alone, called Kocho, were marched to enslavement and death by ISIS. He wrote that five years later, those hundreds of thousands of Yazidis still in refugee and displaced persons camps have difficult returning due to security fears.