Fort D’Issy. Issy-les-Moulineaux

Built in the 1840s as part of the defence structure surrounding Paris, Fort d’Issy quickly became obsolete due to its proximity to the capital. In 2009, work began to transform the site of this pentagon-shaped fort into an eco-district comprising sustainable housing, cultural amenities, green spaces and smart technologies such as underground waste disposal. A pioneer in the climate-change battle.