A few weeks ago, when #MuseumsAreNotNeutral co-creator La Tanya S. Autry (artstuffmatters) heard that the gun used to kill Emmett Till was being acquired by the Museum of Mississippi History and the Mississippi Civil Rights Museum, she found herself wrestling with heavy thoughts and emotions. Mamie Till-Mobley had to fight to bring her son’s body back to Chicago. When she saw the vicious mutilation they inflicted on him, she wanted everyone to witness it. Photos of Emmett Till’s body circulated through the Black press and galvanized a generation, mobilizing Black Americans and launching the Civil Rights Movement. “Yes,” Autry writes, “visibility provoked social action. But Till’s mother largely established the terms of visibility. Emmett Till’s image operated within Black networks, among people with a shared vulnerability to white violence. As a mother and activist, she understood that witnessing can be a powerful tool.” What does it mean to witness the gun that killed Emmett Till...