In this paper, I cover the background and economic history of green buildings, including four case studies. Based on this exploration, I find that green roofs and walls are best suited to dense, highly paved cities with little capacity to expand their sewer systems. Green infrastructure is best suited for stormwater management to avoid combined sewer overflow (CSO) pollution and managing urban heat island (UHI) effects, while at the same time providing many positive externalities for people and the environment. Green buildings take those benefits and fit them into a smaller area (on roofs and walls), which is most applicable where tearing up pavement to provide more ground-level green space and expanding the sewer systems would be too costly.