By the year 2100, the global population is predicted to be 10 billion, 2 billion more than now. Architect Vishaan Chakrabarti sees this as an opportunity to build a more ecologically healthy and equitable world centered on well-designed communities with new forms of affordable, sustainable housing. Drawing from his new book, The Architecture of Urbanity: Designing for Nature, Culture, and Joy, Chakrabarti says that caring for the character and culture of communities can be the key to solving urgent global and political challenges.