Final answer:
The Taliban were the extremists governing Afghanistan during the September 11th attacks, which caused the U.S. to launch Operation Enduring Freedom to overthrow them and dismantle Al-Qaeda's presence in the region.
Step-by-step explanation:
The extremists who governed Afghanistan during the September 11th terrorist attacks were known as the Taliban. This Islamic fundamentalist group ruled Afghanistan from 1996 until they were removed from power by a U.S.-led invasion in 2001. The attack on September 11th, which claimed nearly 3,000 lives, was orchestrated by Al-Qaeda, under the leadership of Osama bin Laden. Following the attacks, the United States launched Operation Enduring Freedom to dismantle Al-Qaeda's training camps, capture Al-Qaeda members, including bin Laden, and overthrow the Taliban government.
The aftermath of the invasion saw a focus on rebuilding civil society and infrastructure in Afghanistan and supporting a democratically elected regime. Due to these events, the War on Terror became a central aspect of U.S. foreign policy, which also included a later military campaign in Iraq. The international military campaign aimed at eliminating terrorist organizations like Al-Qaeda, which had global impacts on security and politics.