Sustainability requires the efficient use of resources. The least carbon- and energy-intensive pattern of settlement today is in compact, walkable cities whose integrated networks of infrastructure that allows us to move, eat, drink, play, and survive extreme weather. As our population shifts to urban and coastal areas, we will need to build more infrastructure systems to accommodate growth and to increase sustainability. Yet we are building too little, too slow to maintain our existing infrastructure, let alone to facilitate next generation systems that will accelerate our society to a truly low-carbon future. Our transportation, water, parks, freight, solid waste, and energy infrastructure systems are crumbling, and new needs such as coastal flood mitigation and resiliency are not being met. With little political will for massive public works programs and current practices that are slow and costly, cities are starting to use innovative ways to deliver these critical assets, including design-build procurement, long-term concessions, private operation, maintenance and financing, and other forms of public-private partnerships. Cities and states are pooling resources to solve problems through infrastructure exchanges and accelerators. They are creatively reimagining and reusing obsolete and neglected land and buildings, and are integrating services to create infrastructure that is multi-purpose, resilient, and sustainable.