From Los Angeles to New York to Kolkata to Singapore, "Cities" highlights inspiring stories of people reshaping urban life and sharing space with wildlife. In Los Angeles, a mountain lion unites a community and becomes the unofficial mascot of the city, while in Kolkata, locals clean the urban wetlands, creating an incredible wildlife habitat and supporting thousands of jobs. In New York City, the Billion Oyster Project is restoring reefs to New York Harbor, helping protect the city from dangerous hurricanes. And in futuristic Singapore, urban reforestation efforts have transformed the city, enhancing citizens' lives and attracting wildlife such as hornbills.