The Seattle Justice Centre is 14-story building housing Seattle's municipal courts and police headquarters in a dense urban setting. Seattle mastered its design challenge to create distinct and unique identities for both the courts and the police headquarters within one sustainable building. It has unique features including: naturally vented "double skin" façade that allows light but minimizes heat, and a "green" roof with drought-resistant and low-maintenance plants that remove solar heat, stores rainwater and filters pollutants out of the air while returning some oxygen to the atmosphere. It cuts 816 tons of CO2 annually and $32,600 in avoided mitigation savings. Utility savings from reduced energy and water use total $113,4000 per year.