We are a US National Science Foundation-supported network of scientists, industry leaders, and policy partners committed to building better cities. We examine physical changes in the scale and scope of infrastructure design, the role of new technologies, as well as the changes in public attitudes and policy that can help achieve the infrastructure transitions needed to build healthy, sustainable, and livable cities today and in the future. We work across key infrastructure sectors—buildings & energy, food systems, green infrastructure, transportation, water & waste—to understand how they shape critical societal outcomes in cities—well-being, health, environment, equity, and livability. Across sectors and outcomes, a core area of our work is directed at exploring interactions, co-benefits, and trade-offs. The network is also explicitly studying key pathways of change for urban infrastructure transitions, spanning technology & design innovation, spatial reconfiguration, business & finance, policy & governance, and behavior change. Developed with support from the US National Science Foundation's Sustainability Research Network (SRN) program, our network connects across nine research universities, major metropolitan cities in the US and India, multi-city organizations as well as infrastructure firms and policy groups to bridge research and education with concrete action in cities.