Millions of people across South America woke up on Sunday, June 16, to a completely dark world. The BBC reported that the entire countries of Uruguay and Argentina, a combined population of 48 million people, were left totally without power. The outage affected parts of Brazil and Paraguay, as well.

Tweets from Edesur Argentina, one of the country’s largest energy providers, explained that “a massive failure in the electrical interconnection system” caused the power outage.

As of now, the country is slowly beginning to restore power, a process that will take “several hours.” Edesur shared a message from Argentina’s Energy Secretary, that stated that a “failure in the Argentine Interconnection System (SADI)” is at fault.

50,000 people have had power restored in Argentina, while coastal cities in Uruguay have had power restored, according to a tweet from Uruguay’s energy provider – which still leaves millions of people without power.

People have taken to social media and posted videos and photos of their darkened cities with the hashtag #SinLuz.