The September 11 Attacks, also commonly known as "9/11" refers to the bombing of the World Trade Center Twin Towers and Pentagon on September 11, 2001 by militant Islamists loyal to Osama Bin Laden - it involved the use of passenger planes as weapons in a forced-suicide attack similiar to the infamous "kamikaze" pilots of World War II.
September 11 is often stated as being amongst the worst terrorist attacks on America, claiming many lives and sparking the international "War on Terror" campaign that continues to play an important role in the world.