From the leaders in the burgeoning urban adventure scene, Jinx magazine, comes this extreme tour of New York City's unseen places - from its sewers and subway tunnels to the pinnacles of its bridges. From abandoned hospitals to epic graffiti murals to the roof of Grand Central Station and the enormous towers of the George Washington Bridge, Invisible Frontier offers a series of gripping true adventure stories and a fascinating trip through the seldom-chronicled aspects of a great city's history, technology and culture.