As the world's largest sources of carbon dioxide and consumers of natural resources, major cities are at the center of three transformative trends shaping the urban future. The first is environmental, requiring cities to reduce their carbon footprint, adopt renewable energy, embrace the circular economy, limit the conversion of natural land into artificial surfaces, and adapt to a warming planet. The second is technological, as innovations in artificial intelligence, electrification, new materials, robotics, sensors, and digital tools are reshaping the design, construction, and operation of buildings and infrastructure. The third involves evolving lifestyles, influenced by cultural, regulatory, economic, and political changes. Leonard, the foresight and innovation platform of the VINCI group, has been observing and guiding these transformations for nearly a decade. Our mission is to explore major trends, support the development of relevant technologies, and connect the actors needed to scale these innovations. As the climate crisis intensifies, we must identify, test, and implement the most impactful solutions to address these challenges effectively. Two priority projects are central to this effort: mitigating climate change and adapting cities to a new climate. Mitigation focuses on reducing greenhouse gas emissions, a global challenge since carbon dioxide affects the planet uniformly, regardless of its source. In the transportation sector, electrification is a key innovation, requiring changes in vehicles, infrastructure, charging networks, and usage patterns. Similarly, the construction industry must transition to low-carbon materials and practices, including the redesign of concrete and other high-emission materials. A systemic approach is necessary, combining low-carbon materials, reuse of resources, eco-friendly design, building renovations, and improved resource management. Water management is another example of this systemic shift. Traditionally, cities have focused on quickly draining rainwater, but future urban planning must retain, reuse, and integrate rainwater into neighborhoods to reduce flooding, conserve resources, cool urban areas, and enhance soil resilience. Adapting to climate change is equally critical, as cities must prepare for increased heatwaves, water scarcity, extreme weather events, and the vulnerability of infrastructure and soil. While solutions exist, their implementation has been too slow. Measures such as cooling urban spaces, reducing heat islands, increasing green areas, and improving water collection and reuse require urgent and collective action. However, challenges like complex funding, the mismatch between climate urgency and urban planning timelines, and lack of coordination have hindered progress. As climate impacts become more severe, adaptation is no longer an optional concern—it is essential for the continued viability of cities. Addressing these challenges requires collaboration among diverse stakeholders. No single entity can tackle urban transformation alone. Urban innovation must be open, involving companies, local governments, researchers, startups, investors, architects, engineers, policy experts, digital professionals, artists, and citizens. Cities are complex systems, and sustainable transformation occurs when expertise intersects, solutions are tested and refined, and innovations are deployed. Since its founding in 2017, Leonard has been committed to this collaborative approach. We support initiatives from VINCI employees and external actors to identify and advance solutions to today’s and tomorrow’s urban challenges. We also incubate between 40 and 50 projects annually in construction, mobility, and energy. As Leonard approaches its tenth anniversary, we aim to expand this collaborative dynamic, especially internationally. While urban challenges are global, solutions must be tailored to local contexts. By sharing methods, experiences, and collaborations, we can develop effective innovations to prepare for a future where climate, technology, and lifestyles have changed dramatically.