This essay analyzes the dynamics of absence and presence at the 9/11 memorial and museum in New York, as elements of their design and aspects of the haunting of the site. Of the 2753 victims, 1113 have never been identified, despite a huge and expensive forensic identification process, and this absence has been a shaping force at the site. While the designs of the memorial and the museum both evoke absence, both also attempt to render the dead present, through naming at the memorial and through an array of media, most effectively audio, in the museum. This essay examines the complex forensic identification of the 9/11 dead and the effect of the disappearance of so many, and analyzes the strategies through which the memorial and museum aim to render the 9/11 dead present.