A woman looks out at One World Trade Center from inside the 9/11 Empty Sky memorial at Liberty State Park in Jersey City, N.J., on Wednesday. Americans commemorated the 12th anniversary of the Sept. 11 attacks with solemn ceremonies and pledges to not forget the nearly 3,000 people killed. Gary Hershorn/Reuters/Landov hide caption

itoggle caption Gary Hershorn/Reuters/Landov

A runner heads down the banks of the Charles River in Cambridge, Mass., in front of the Boston skyline at dawn, the morning after deadly explosions at the Boston Marathon. Charles Krupa/AP hide caption

itoggle caption Charles Krupa/AP

Information in the files is largely from interrogations of detainees being held by the U.S. at Guantanamo Bay, Cuba. (Sept. 16, 2010, file photo taken at Guantanamo Bay.) John Moore/Getty Images hide caption

itoggle caption John Moore/Getty Images