Today we honor those lost on September 11, 2001, the brave first responders who sacrificed their safety and all those who have served our country since the attacks.

Intrepid retired from active duty in 1974 after serving in World War II, the Cold War and the Vietnam War. Decades later, when another call to service came, Intrepid answered and served once again, this time as a secure emergency operations center. The ship’s unique access to sea, air and land—along with its proximity to Ground Zero—made it an ideal location for the FBI and other law enforcement officials to launch the initial investigation. On board the ship, they worked together to field half a million phone calls and gather important intelligence.

All flags at the Intrepid Museum will fly at half-mast today in honor of the countless acts of courage, compassion and service on that day 15 years ago and every day after.