Deep under the hills of southern Brazil and northern Argentina, scientists found huge tunnels that appear to be cut into solid rock. They say no human or geological process created them.
They do not follow river channels, they show no signs of…
Deep under the hills of southern Brazil and northern Argentina, scientists found huge tunnels that appear to be cut into solid rock. They say no human or geological process created them.
They do not follow river channels, they show no signs of…