The Urban 20 (U20) is “a city diplomacy initiative that brings together cities from the G20 member countries with the aim of promoting debate and the political articulation of recommendations on the economic, climate and development agendas in cities” (G20 Brazil 2024, 2024).

Created on December 12, 2017, during the One Planet Summit in Paris, the U20 emerged under the leadership of the then mayor of Buenos Aires, Horacio Rodríguez Larreta, and the mayor of Paris, Anne Hidalgo, and has since consolidated itself as an official G20 engagement group, which aims to establish a forum for cities to articulate local perspectives and common objectives in strengthening their role in Global Governance. In this sense, the U20 brings together mayors from the main G20 cities to advance the role of cities in formulating local solutions to global problems.