In cities around the world, street lights, public transit systems, and electric meters are already connected to the internet. Soon, smartphone controlled, self-driving cars will roam cities and every part of the urban fabric could be Wi-Fi enabled. While tomorrow's smart cities will usher in efficiencies and convenience, they'll also bring about security threats and vulnerabilities. Hackers have already demonstrated they can remotely take over cars and switch off traffic lights. So, how can urban planners and engineers build cities of the future that are resilient enough to guard against cunning criminal hackers who may want to bring Singapore or San Francisco to a grinding halt?