Thirty-four Jews who died serving as slave laborers for the Nazis were honored with the dedication of gravestones in a ceremony at the US Army airfield where their mass grave was recently discovered, the US military said Monday. More than 200 mourners were on hand for Sunday's ceremony to mark International Holocaust Remembrance Day, dedicating the gravestones to the anonymous victims of the Echterdingen concentration camp that were discovered in September 2005 during construction work at the airfield. Benjamin Gelhorn, a survivor of the Nazi camp system who spent three months at Echterdingen, said the Kaddish prayer of mourning to close the ceremony, the US European Command said in a statement. "The Lord gave me the power to be here in 2007 and to make the Kaddish for these people," Gelhorn, 86, was quoted as saying. "I'm really happy I'm alive."