From Washington: A solemn commemoration marked a significant milestone. The lives lost in a tragic event were honored. Nearly 3,000 people were killed in the incident.

The agency responsible for protecting the nation's transportation systems has remained committed to its mission. Its goal is to ensure people and commerce can move freely.

Further details about the commemoration and the agency's work are available from the source. The agency's mission has not changed since its creation, and it continues to work towards protecting the nation.