Hannah pauses at the stairs. Be very careful, she says, with the confident authority of an explorer that has made the journey many times before. I watch where she places her feet, only on the outside six inches of the stringers, where the balusters used to be. Towards the middle, the treads are charred, some are even split in two. Below us, the black murk of the basement. A tumble might mean severe injury, even death. I carefully follow, to the landing at the top of the stairs. We take a few steps forward, suddenly find ourselves standing in the middle of Hannah's once-bedroom. I am amazed by her courage to revisit this place, even if it is hallowed ground. In here, ground zero, where the devastation was most extreme, the flames the hottest, the smoke the thickest. In here, two young girls died in the scantest of moments, less time than it takes to walk to the corner and back.