World Metropolitan Day is observed worldwide on October 14 to commemorate the adoption of the Montreal Declaration on Metropolitan Areas and to highlight the significance of metropolises. The day was inaugurated in 2018 and was originally celebrated on October 7 before being moved to October 14 starting in 2024. It brings together mayors and metropolitan leaders from around the globe, providing a platform for exchanging knowledge and solutions aimed at promoting sustainable urban development. Events typically include summits, conferences, and panel discussions, with each edition focusing on a unique theme related to urban sustainability. The campaign is coordinated by Metropolis, a Barcelona-based organization, and UN-Habitat, a UN program dedicated to sustainable urban development. Notable past themes have included “Resilience for all: creating caring metropolises beyond COVID-19” and “Crossing Boundaries.”