World Cities Day brings Urban October to an end on 31 October each year and was first celebrated in 2014. As with World Habitat Day, a global observance is held in a different city each year and the day focuses on a specific theme.

On 31 October 2025, the Global Observance of World Cities Day, was linked to people-centred smart cities. It showcased how data-driven decision making, technology, and AI can be used to improve urban life and recover from current shocks and crises. It also focused on promoting smart city initiatives centered on people.