We are going to be visiting some of the most important sites of New Amsterdam, and we can do this because the street grid of lower Manhattan is largely unchanged from the mid-1600s. And we know this because of a survey and map of the city made in 1660. There were about 1,500 residents in 300 houses in 1660, and we know the names of most of them. The original map was lost to time, but a redraft of it was part of an atlas sold to Cosimo III de’ Medici, Grand Duke of Tuscany around 1667, and it was rediscovered in 1900 in villa di Castello, hence its name, the Castello Plan. A bronze relief of this map is embedded in a rock located at State Street & South Ferry, not far from where General Stuyvesant’s house, Whitehall, stood. The New Amsterdam History Center has recently brought the map to life with an interactive 3-D model.