Shorthand for September 11, 2001. A terrorist attack involving two planes hijacked by Al-Qaeda terrorists flew into the Twin Towers, causing them to collapse top-down onto the streets of New York City. Another plane was flown into the Pentagon building in Arlington, Virginia while a fourth, presumed to be targeting somewhere in Washington D.C. was deliberately crashed near Shanksville, Pennsylvania as its passengers fought to regain control from the terrorists. The death toll is currently at 2,996, including 17 hijackers.
The event is widely considered by Americans to be the true start of the 2000s, as well as a catalyst of the "War on Terror", a series of armed involvement of the US and allies in the middle east under the pretext of eliminating terrorism. Chief among these conflicts were as the American invasion of Afghanistan in 2001 and Iraq in 2003, and to an extent, the Syrian Civil War.
Due to various factors, the event has spawned numerous jokes and memes. The earliest was about various conspiracy theory alleged that the event was an inside job orchestrated by then-US President George W. Bush as a casus belli for the war in the middle east, such as "Bush did 9/11" and "jet fuel don't melt steel beams". Though later on, 9/11 imagery or reference has gained resurgence as a part of Gen Z humor, primarily for the shock value or as an "edgy" punchline.
The most common depiction of the event depicts smoke exiting either of the towers.
