Brazil Is Home to Prehistoric Underground Tunnels Created by Giant Ground Sloths
While you may have heard of underground cities built by humans, what about huge tunnels dug by giant prehistoric sloths? Though it may sound outlandish, it's actually what one finds across southern Brazil. Known as paleoburrows, these enormous tunnels can measure up to 2,000 feet long and over six feet tall. Shockingly, the existence of these caves was relatively unknown until a Brazilian geologist noticed something while driving down the highway.