Fidel Castro once called Cuba’s power plants “prehistoric.” But the country still relies on them, contributing to the longest blackout since the collapse of its former patron, the Soviet Union.

Cuba’s government says some electricity has been restored on the island after one of the country’s major power plants failed and left millions without electricity in an outage that started two days earlier.

A few things to know after millions of people in Cuba were left without electricity for two days when the nation's electrical grid collapsed