In many respects, New York City is an unnatural wonder, quite unlike any other American city and also unlike megacities in other industrial countries. Its government and politics, its physical attributes-like the celebrated skyline and high population density-and many of its social characteristics-like the extraordinarily high percentage of the city's population that is foreign-born-are different. But New York City at the same time shares with other American cities an array of political and governmental institutions, practices, traditions, and pressures, ranging from the long dominance and then long decline in the role of party organizations in local government to the city's ultimate dependence on outside actors and forces to shape its political destiny.