In a city this vast, a handful of terrible events acquire the power of parable and mark neighborhoods for decades. The 1964 death of Kitty Genovese, a lone woman tracked and stabbed by a killer on a leafy Kew Gardens street while her neighbors averted their eyes and failed to call the police, became a national symbol of urban anomie. In Bensonhurst in 1989, 16-year-old Yusef Hawkins was shot and killed for the mistake of being black in a white neighborhood. In death he came to personify a city’s undigested racial rage and a black community’s search for justice.

Who knows where a murderous rampage in Greenwich Village or a fire that killed 10 people, 9 of them children, from two Malian families might stand in the dark annals of a city’s history?

“One of a great city’s functions is to serve as a repository of memory,” said Francis Morrone, a historian and lecturer on the culture of the city. “We need to be a place that preserves not just happy times and grand buildings, but those memories that affect us on the deepest level.”