If there's nowhere else to put it, pile it right on top! That's the philosophy behind urban green roofs, which add much needed green space to otherwise uninviting city landscapes. This video takes us to two of New York's most impressive green roofs to find out how they can help cities cool off and clean up. At state of the art research station on the roof of Silvercup Studios in Queens, we talk to green roof specialist Leslie Hoffman about how a few plants can reduce water pollution, cool an "urban heat island" by 100 degrees, and improve air quality. And at the top of the Solaire in Manhattan, it's easy to feel cool while hanging out in their plush roof garden that adds beauty to functionality. These are some of the first green roofs in New York, and for the future the sky's the limit. Less