Nuclear weaponry is both far far less powerful than it was during WW2 and the Cold War, and the buildings are also much much stronger. It's estimated that you'd

Nuclear weaponry is both far far less powerful than it was during WW2 and the Cold War, and the buildings are also much much stronger. It's estimated that you'd need some 40+ of today's warheads to completely destroy NYC. You have to expect some to get shot down, so it's not one-to-one targeting.