This summer I worked at the World Bank in the Global Urban Development and Resilience team to develop a low carbon planning tool for cities. The tool's objective is to help cities identify and prioritize different climate mitigation interventions to achieve maximum emissions reductions at minimum cost. This tool will allow cities to accurately model their emissions across various sectors including buildings, waste, wastewater, and transportation. To run the model, a city can either enter emissions, energy, building, waste, wastewater and transportation data for their own city, or select a proxy city with similar demographics and climate. Considering factors such as a city's budget, work force, etc., the tool will then recommend localized policies and technological solutions that the city can adopt to reduce its overall emissions and energy consumption. The tool will initially be deployed in cities in developing countries, with the eventual goal of being used worldwide. This tool will have a tremendous global impact, and I am very fortunate to have had the opportunity to work on developing it this summer.