Boston is a terrifically walkable city in many parts--I don't even really agree with the people saying it's significantly worse than major European cities. I have a much easier time doing things like grocery shopping here than I did in London, and there's more green space with a purpose. If you follow the Emerald Necklace, you can actually get from your home to work while not having to cross many street at all. London and Paris have breathtaking parks, but they're generally in contained spaces, rather than snaking through the city.