The National September 11 Memorial and Museum is a nonprofit institution at the World Trade Center site, established in 2005 to tell the story of the 1993 and September 11, 2001 attacks through personal narratives and a collection of monumental and authentic artifacts. Architect Michael Arad's design, "Reflecting Absence," was chosen in 2004 from more than 5,200 entries; the memorial's twin reflecting pools, set within the towers' footprints and ringed by swamp white oak trees, opened in September 2011, with victims' names inscribed on bronze parapets. The underground museum, holding tens of thousands of images and artifacts, opened to the public in May 2014. Notable elements include the Survivors' Staircase, the Last Column, a damaged FDNY fire truck, and the Survivor Tree, a Callery pear recovered from the rubble.