Watch the full episode here: youtu.be/HeR2Ghwzn8k Billions of years ago, another planet smashed into Earth. An event of this epicness could have created our Moon. It also could have brought alien life to our planet. What evidence of this planet still exists on Earth today? Could there be life deep inside the Earth’s surface? And could that life be an advanced civilization of humanoid aliens? Would it be possible for subterranean cities to exist within Earth? Get the What if 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 Interested in sponsoring our episodes or collaborating? Email us: contact@underknown.com Our other channels: How to Survive: bit.ly/how-to-survive-show Aperture: bit.ly/aperture-show T-shirts and merch: bit.ly/shopwhatif Newsletter: bit.ly/whatif-newsletter What If elsewhere: Discord: discord.gg/Bj5UnspbwE Whatsapp:...