September 11

Notable historical events

Like many calendar dates, September 11 has been the anniversary of several widely remembered events. The date is most commonly associated with the attacks in the United States on September 11, 2001, often referred to simply as "9/11." Media and public discourse use the shorter form frequently; see commentary on the term at media coverage. On that morning, hijacked passenger airliners were flown into New York City’s World Trade Center complex and into the Pentagon near Washington, D.C.; a fourth aircraft crashed in a field in Pennsylvania after passengers attempted to regain control. The attacks were carried out by an international terrorist organization and killed and injured thousands of people, prompting global responses in security and policy; the World Trade Center and the Pentagon are commonly referenced locations in discussions of that day (World Trade Center, The Pentagon), and the events took place on U.S. soil (United States).

Other significant occurrences

• September 11, 1973: A military coup in Chile overthrew the elected government, a turning point in Chilean history.
• Various political, cultural and local events worldwide also fall on this date, so its meaning can vary by country and community.

Remembrance, observance and legacy

The 2001 attacks led to annual commemorations, memorials at the attack sites, and official observances such as moments of silence. In the United States the date is observed in different ways at national and local levels; educational programs, memorial ceremonies and museum exhibits examine the events and their consequences. The long-term effects include changes to aviation security, emergency response practices and international counterterrorism cooperation.

Language, culture and usage

In English and other languages the numerals "9/11" have become a compact label for the 2001 events; the date itself remains part of the ordinary calendar and is used in contexts ranging from weather records to cultural anniversaries. Because the name carries strong associations, writers and speakers often specify whether they mean the calendar date or the historical events when using the term.

Further reading: for discussions of media terminology see coverage and analysis; for chronological context consult sources about the Gregorian calendar and leap years. Related site references include the locations most commonly mentioned in accounts of the 2001 attacks: the World Trade Center, the Pentagon, and resources on policies in the United States.