1) Abu Musab al-Zarqawi formed al-Tawhid wal-Jihad in 2002 and led it until his death in 2006 when it merged with al-Qaeda in Iraq and became known as al-Qaeda in Iraq. 2) ISIS gained strength in Iraq and Syria between 2013-2015, taking control of key cities like Mosul and Raqqa. They established a caliphate, implemented sharia law, and generated revenue through oil sales, taxation and looting. 3) ISIS attracted thousands of foreign fighters to its ranks through propaganda promoting ideals of caliphate, justice, and identity. Its numerous violent attacks worldwide have had a significant impact globally.