The World Before Your Feet

For more than six years, Matt Green, 37, has been on a deeply personal mission. He's walking every block of every street in New York City -- a journey of more than 8,000 miles.

In order to fulfill his quest, Matt quit his job as an engineer, gave up his apartment, and discarded most of his possessions. He now couch-surfs through apartments across the boroughs, living on about $15 per day. When he's not out walking, he spends his time researching the myriad curiosities that catch his eye along the way, from national landmarks to humble manhole covers. Why undertake this journey? Perhaps the more salient question is, why not?