September 11

A photo taken on the 18th anniversary of the Sept. 11 terror attacks appears to show clouds shaped like a firefighter running toward an angel. 

While the date of Sept. 11 often carries a sadness with it for many Americans in remembrance of the horrific terrorist attacks that took place in 2001, the day has also become a joyous one for a couple in Tennessee.

Americans are commemorating 9/11 with mournful ceremonies, volunteering, appeals to "never forget" and rising attention to the terror attacks' extended toll on responders.

A firefighter from Long Island who died in the World Trade Center attacks was remembered for a second time on the eve of the 18th anniversary of 9/11.

On September 11, 2001, a total of 19 terrorists hijacked four airplanes, crashing two of them into the World Trade Center, one into the Pentagon and the fourth into a Pennsylvania field, killing thousands of Americans in the process and wreaking destruction that, in its aftermath, has continued to claim lives.

On September 11, 2001, more than 2,600 people perished at the World Trade Center, 125 people died at the Pentagon and 256 people died on four airplanes after terrorists hijacked the planes and turned them into guided missiles.

For students from elementary to high school, the Sept. 11 terrorist attack isn't a memory. It's history. A new HBO documentary that debuts on the event's 18th anniversary treats it that way.

New York public schools will observe a moment of silence Wednesday to remember those killed on 9/11 — it's the law.