Some 21,000 succulents call the roof of New York City’s Con Edison’s three-story Learning Center in Long Island City, Queens. The facility – some pales in comparison to the 2.5 living roof atop the Postal service facility in mid-town Manhattan. Meanwhile Chicago, the city that plays host to more green roofs than any other US City, added some 600,000 square feet of green roofs last year bringing their total coverage to a whopping 7 million square feet according to a December Yale Environment 360 article. The city of Toronto even went so far as to mandate that new buildings above a certain size will have to cover at least 60% of their roofs with vegetation.