☆ In America the convention is to write the month first , followed by the date ; hence the short form '9/11 ' .
Explanation:
On 11 September 2001 , nineteen hijackers hailing from a number of Arab countries took control of four American commercial aircraft shortly after takeoff and flew them into important buildings in the US .
One airliner each crashed into the northandsouthTowersoftheworldTradecentreinNewYork.
A third aircraft crashed into thePentagonbuildinginAirlington,Vírginia, where the US defence Department is headquartered
The fourth aircraft , presumably bound for the CapitolbuildingoftheUSCongresscame down in a field in Pennsylvania.
The attacks have come to be known as " 9/11".
The attacks killed nearly three thousand persons. In terms of their shocking effect on America , they have been compared to the British burning of Washington, DC in 1814 and Japanese attack on pearl Harbour in 1941 .
However, in terms of loss of life , 9/11 was the most severe attack on US soil since tge founding of the country in 1776.