Most of this is due to a relatively new phenomenon: <a href="http://en.wikipedia.org/wiki/Crabgrass_Frontier:_The_Suburbanization_of_the_United_States" rel="nofollow">http://en.wikipedia.org/wiki/Crabgrass_Frontier:_The_Suburba...</a><p>The concept of a 'front lawn', or even of easy access to nature in general, has not always been as popular as it is today. As Jackson notes, a front lawn is rather useless except as a status symbol (unlike a back lawn, people rarely use the front lawn for barbecues, etc.), and they can cut the amount of available space in a neighborhood by 50% or more, making them a truly luxury expense.<p>But this popularity wasn't always so widespread - and n fact, it isn't even so commonplace in some parts of the world today (though the Westernization of global cultures has changed this somewhat).<p>For those who are interested, the most expensive zip codes in New York are 10014 (by real estate) and 10128 (by income). The poorest would probably be 10451 (South Bronx).<p>Contrast those both to 10025 and 10027, the border of Harlem (poor, but rapidly gentrifying, historically black) and the Upper West Side (historically well-off for several decades, also a large Jewish community).