The 9/11 attack, carried out by the terrorist group Al-Qaeda, was a culmination of several factors that had been brewing for years. Al-Qaeda, founded by Osama bin Laden, was driven by a radical interpretation of Islam and sought to establish a global caliphate. One of the primary motivations for the attack was the U.S. military presence in Saudi Arabia, home to the holy sites of Islam. Bin Laden saw this as a violation of Islamic holy land and considered it a direct threat to the Muslim world.

Another significant factor leading to the attack was the history of U.S. involvement in the Middle East. The United States had supported dictators and regimes in the region, such as Saddam Hussein in Iraq, to protect its interests. This support often came at the expense of the local population, leading to resentment and anger.

However, it was the U.S. support for Israel that particularly enraged Al-Qaeda. The unresolved Israeli-Palestinian conflict and the perceived bias towards Israel in U.S. foreign policy were seen as an affront to the Muslim world. These grievances, combined with the radical ideology of Al-Qaeda, fueled the desire for a spectacular attack targeting the U.S.