From global conflicts to climate change, the world faces challenges no country can tackle alone. Erik Solheim, former UN under secretary general and executive director of the United Nations Environment Programme, says stronger multilateral cooperation and deep reform of the United Nations are essential to addressing these challenges. In an interview with CGTN on the sidelines of the Global Governance Forum in Xiongan, he also highlighted how Xiongan's integrated planning and smart city development could offer valuable lessons for cities around the world.