Green roofs are gaining popularity in commercial and residential design, offering a nearly untapped, limitless space to plants perennials, shrubs, even trees. They also cool the air in and above our homes and offices, absorb carbon dioxide, return oxygen, reduce runoff, filter pollutants and provide habitats for birds and other wildlife. They even offer a welcomed respite for mind and body. In this episode, we get a rare, behind the scenes tour of the famous rooftop gardens at Chicago's city hall. We also visit Lurie Garden at Chicago's Millennium Park, and demonstrate how to implement a smaller homegrown version. In the kitchen, Chef Nathan uses one of the most common roof top vegetables, the tomato, to create a delicious meal.