New York is more fast-paced and far more dense. It's more obvious exactly what is open late until 4 a.m. and what isn't. The city has an energy that stretches the limits of how long you think it is possible for a human being to be awake. Public transportation is very, very cheap and it's fast to get from one side of the city to the other. On average, if you were to pick a random restaurant, I think the food is better.

London is more like a collection of villages that have grown into each other over 1,000 years. It's lower density and I believe it takes longer to get from one side of the city to another. The Tube only runs until 12:30 or 1 a.m. (But the really edgy part of London -- Hackney & Dalston -- is only a short bus ride or maybe even walking distance from the financial center if you're liberal about what you consider its boundaries.

But in both cities the perceived threat of terrorism is real. How real? How much is fabricated?