City leaders from around the world are showcasing real solutions for climate action at the C40 World Mayors Summit in Rio de Janeiro ahead of COP30. The theme of the summit is "Mutirão in Motion: Cities Leading the Way to COP30" and highlights Brazil's tradition of community collaboration to build solutions. Initiatives such as the Global Methane Hub and the Urban Planning Accelerator are being launched to support cities in cutting methane emissions and integrating climate and equity into city master plans. Mayors are calling for increased funding for urban climate finance and are pushing for the 'Baku-to-Belém Roadmap to $1.3 trillion' to mobilize public and private investment in cities, states, and regions, especially in the Global South. Investment in electric bus fleets in Brazil, Chile, Colombia, and Mexico has surged to US$4.3 billion, with a partnership aiming to drive port decarbonization through a $1 billion Global Port Sustainability-Linked Loan initiative. Mayor Sadiq Khan emphasizes the importance of cities in addressing climate change and building a sustainable future, while Mayor Eduardo Paes highlights the role of C40 cities in reducing emissions and creating green jobs. Mark Watts, Executive Director of C40, discusses China's "irreversible" green transition and growing global ambition, with efforts in transitioning to a more sustainable economy seen as a positive development in the fight against climate change, influencing other nations to follow suit. This shift towards sustainability is crucial in addressing the climate crisis and creating a more environmentally friendly future.