Just 25 cities produce 52% of the world’s urban greenhouse gas emission, but cities all over the world are looking to modernize their infrastructure to create a more sustainable future. These cities understand that smart is a journey, not a destination. GIS is essential to create Smart City Twins of the natural and built environment. It uniquely integrates many types of digital models and enables the ability to build out proposed futures. In this presentation we will highlight and showcase different tools and workflows to design a more sustainable future for cities all over the world.