This document discusses smart cities, including their architecture, types, key areas, and implementation challenges. It outlines a 4-layer smart city architecture consisting of user, service, infrastructure, and data layers. It also discusses types of smart cities and key areas like smart energy and smart transport. The document identifies challenges like data confidentiality and availability. It presents a risk assessment matrix to evaluate risks like those posed to smart energy, transport, and data. Finally, it concludes that cyberattacks, malware, and availability are major smart city threats and that applying controls to networks and communications poses the highest costs.