A warship built with steel salvaged from the World Trade Center has been put into service in New York. Hundreds of U.S Navy officers and sailors and also families of 9/11 victims attended the commissioning of the warship in New York's Manhattan.<br/> <br/>The bow of amphibious assault ship has 7.5 tonnes of melted steel from the debris of the World Trade Center. The ship's crest includes images of the Twin Towers and features the colours of the city departments that first responded to the terrorist attacks in which nearly 3,000 people died.<br/><br/>The one billion dollar ship was built in Louisiana last month.<br/>