Our power grid is complicated enough to count as a complex system, in which changes in any one part can have unexpected effects on other parts. For example, the great northeast blackout of 2003 was caused by a small error that cascaded , causing failures in larger and larger swaths to the system. Thus, a power-line contacting a tree near Cleveland led to the lights going out in New York City. To prevent serious damage, automatic shutoffs are usually installed. However, while this prevents the need for expensive repairs, it also greatly increases the chances that a cascade will start in the first place. This is likely the causal factor in the famous Super Bowl blackout of 2013. The setting for a relay was set too low, so it “…activated the switch gear, which is designed to cut some power to isolate any problem and prevent system damage and a larger outage.” Therefore, learning about complexity theory, especially as it applies to power systems, is very important.