Leave the World Behind: An entertaining film, but an unrealistic take on a nationwide cyber attack. Localized outages could occur in a similar scenario, but radio, satellite, coaxial cable and more provide additional communication infrastructure that would prevent the world from going into armageddon mode overnight. If you’re looking for a more grounded depiction of an attack on our electronics and systems, I would refer you to the novel One Second After, where a nuclear EMP is set off. bit.ly/48EKiB6