Sept 11, 2001 -- a day the nation will never forget. A day thousands of emergency responders and civilians risked their lives to save others. A day when the nation came together in the face of unimaginable tragedy ...

25 years after the Twin Towers in New York City were struck by hijacked American Airlines Flight 11 and United Airlines Flight 175, we remember the nearly 3,000 lives lost, we honor those affected, and we never forget the lives lost and the devastation of that day.

The harrowing photos from that tragic Tuesday captured moments of unimaginable fear, heartbreak, and courage.

The Pentagon was also targeted that morning, when American Airlines Flight 77 was hijacked and crashed into the building, killing 184 people.

We also remember the 44 lives lost on United Airlines Flight 93 that was also hijacked but crashed into a field in Pennsylvania.

Twenty-five years later, these powerful images remain a haunting reminder of the lives lost and the selfless bravery of those who rushed to help.

Look back at these unforgettable images.