Brazilian scientists have discovered a new river in the Amazon basin, but it’s not a place to go swimming with piranhas, it’s actually underground, around 4km beneath the Amazon river.

(They’ve called it The Rio Hamza, after the head of the team of researchers who discovered it, and it appears to be as long as the Amazon river but up to hundreds of times wider.

It was located using data collected inside a series of 241 abandoned deep wells that were drilled in the Amazon region by the petrochemical company Petrobras in the 1970s and 1980s. I wonder if anyone shouted, “Hey! We’ve hit water!”)