Much of the infrastructure required to create a smart city is in place in a fast-growing number of cities around the world, and leading cities have deployed what they consider to be applications with the highest returns on investment (ROIs) in terms of efficiencies and safety (Figure 1). Other cities are moving ahead from this incipient stage, with growth paths charted by the numbers and types of applications they plan to deploy. Now, innovators are shaping new plans for what smart cities can become as they evolve and mature. The Second-Generation Smart City The smart city industry is projected to constitute a US$400 billion market by 2020, according to TechRepublic. The U.K.'s Economic and Social Research Council predicts that smart city revenue will reach US$88.7 billion by 2025. Technology adoption has driven the pace of smart city development. Now, two forces-a surge in data from networked devices and the proliferation of the Internet of Things (IoT)-is ushering in a second generation of smart cities. The monumental growth in data over just a few years is powering a wave of new applications. The IoT enables ubiquitous sensing and new network infrastructures. The growth of the smart city is a macrolevel move to manage every aspect of cities and to do so in real time. This transition means shedding manual, disconnected systems in favor of automated, connected systems in virtually every industry and municipal environment. IEEE Electrific ation Magazine / S EP T EM BE R 2 0 1 9 7