Watch the full episode here: youtu.be/GxyjWhz5VT0 Millions of years ago, Earth looked very different. All the continents were fused into one, teeming with life that was both beautiful and terrifying. When you think of prehistoric times, you might picture a T. rex rampaging through the jungle with its razor-sharp teeth. But even before the dinosaurs, there were other giant creatures ruling the Earth. Questions or concerns? Contact us at underknown.com/contact Interested in sponsoring our episodes or collaborating? Email us: inquiries@underknown.com Get our 100 best episodes in one mind-blowing book: bit.ly/ytc-the-what-if-100-book Join this channel to get access to perks: youtube.com/channel/UCphTF9wHwhCt-BzIq-s4V-g/join Get a Cameo by Peter: cameo.com/whatifguy Check out our other channels: How to Survive: bit.ly/how-to-survive-show Aperture: bit.ly/aperture-show Your Body On: bit.ly/your-body-on-show Watch ...