Who turned the lights out?

On 28 September 2003, Italy suffered a nearnationwide power cut (Sicily was spared) that also brought down the Internet. Buldyrev et al. take this event, typical of a number that have occurred worldwide in recent years, and examine how such a cascade of failures involving independent networks can occur. They find that, surprisingly, a broader degree of distribution increases the vulnerability of interdependent networks to random failure — the opposite of what happens in a single network. This highlights the need to consider interdependent network properties when designing robust networks if a random failure is not to have catastrophic results. [Letter p. 1025; News & Views p. 984; www.nature.com/podcast]