Exploring the unknown has gotten increasingly difficult in the Google Maps/travel blogger/social media era. So what’s left to explore? Where can a traveler go to cut his own path? The answer may be under your feet, or way up above the rooftops. For this group of intrepid Instagrammers, that’s precisely where they’re going — to the forgotten undergrounds and vertical spaces of New York City. And they’re sharing they’re discoveries and epic viewpoints on Instagram.