The Amazon is the second longest river in the world, snaking through large parts of South America. But just last week, scientists announced they’ve found another river that’s just as long but much wider – and it’s actually underneath the Amazon.

Researchers from Brazil’s National Observatory say the river, called Rio Hamza, is about 4 kilometers below the Amazon, underground. It ranges between 200 and 400 kilometers in width, while the Amazon is only between 1 and 100 kilometers wide. Rio Hamza starts in the Acre region under the Andes and flows through several of the Amazon’s basins before it empties out into the Atlantic Ocean.

Great find!