Steel from the World Trader Center north tower floors 97 and 98, left, is displayed at the National Sept. 11 Memorial Museum, Wednesday, May 14, 2014, in New York. The museum is a monument to how the Sept. 11 terror attacks shaped history, from its heart-wrenching artifacts to the underground space that houses them amid the remnants of the fallen twin towers’ foundations. It also reflects the complexity of crafting a public understanding of the terrorist attacks and reconceiving ground zero. (AP Photo)