As the United States marks 25 years since the Sept. 11, 2001, terrorist attacks, Americans across the country are gathering to honor the nearly 3,000 people who perished and reflect on the day that forever

changed the nation.

Loved ones of those killed, survivors, first responders and politicians are scheduled to attend ceremonies in New York City, at the Pentagon in Virginia and outside Shanksville, Pennsylvania.

A quarter-century has passed since terrorists hijacked four commercial airliners in the deadliest attack on American soil. Today, almost one in four Americans have no personal memory of that day.

Yet, for many others, the tragedy remains etched in their memory. So do its lasting impacts: the global war on terror, backlash against Arab Americans, long term health issues and rise in government surveillance.