Above the streets of Manhattan, tourists meander beside New York joggers along a densely planted trail. To the East, the view of the Hudson River is unimpeded and towards the West, the view is of the hustle and bustle of city life. This elevated park was formerly a freight rail line that was decommissioned in 1980 and forgotten about. However, thanks to an urban planning competition in 2001 that called for the redesign and retention of the New York “High Line”, for the past five years we have had the longest green roof in the world at 2.3 km, right in the heart of Manhattan.