A view of the New York City skyline, as seen from the Empire State Building on September 10, 2001.

A storm passes over New York City on the evening of September 10, 2001.

On September 11, 2001, 19 militants associated with the Islamic extremist
group al Qaeda hijacked four airplanes and carried out suicide attacks
against targets in the United States. Two of the planes were flown into
the twin towers of the World Trade Center in New York City, a third plane
hit the Pentagon just outside Washington, D.C., and the fourth plane
crashed in a field in Shanksville, Pennsylvania. Almost 3,000 people
were killed during the 9/11 terrorist attacks.