The victims and first responders of the September 11 terrorist attacks have been memorialized in a variety of ways over the last 12 years, and a unique tribute by the Navy recently became the latest. The USS Arlington was officially commissioned in front of thousands at Naval Station Norfolk and was dedicated to the 184 people who died when American Airlines Flight 77 slammed into the Pentagon, reports The Associated Press.

The state-of-the-art warship is the third such vessel to be launched as a tribute to those who perished that day, but this one features a unique memorial. Artists forged around 200 pounds of steel that were salvaged from the wreckage into a pentagon that will always be located on the ship as a solemn reminder of the tragedy. Cmdr. Darren Nelson, the ship's operating commander, knows he has a mission, but he also understands the Arlington's importance.

"We are not a memorial, we are a warship. But we carry the spirit of those 184 people that died that day. We know why we got our name," he told the AP. "We teach that to the crew. Every crew member that shows up on board this ship learns and understands that 184 people gave their life for us."

In 2009, the USS New York was officially commissioned. As a tribute to those who died at the World Trade Center, the ship was constructed in part by using steel collected from Ground Zero.