Of all the mysteries on Game of Thrones, perhaps the most mysterious is the question of what would happen if the Wall fell. The short answer is that the undead hordes commanded by the Night King would sweep down into Westeros and kill a lot of people before Daenerys flew in with her dragons to melt them all. (This is based on nothing more than fantasising for about five seconds.)But one intrepid Redditor asked the question that none of us have thought to ask: What if the Wall melted? Presuming that Westeros falls victim to the same climate change currently annihilating Earth’s polar ice , would a melting wall of ice cover Westeros in water?So let’s follow along with some math, starting with the size of the Wall . It’s more than 700 feet high, 300 or more miles long, and wide enough "that a dozen armoured knights can ride abreast at the top of the Wall." ScouseAdler, the source of this math, estimates about 15 meters, which seems reasonable. So if we say that the Wall is entirely ice, and not just a structure that has iced over due to weather, that gives us 1,542,555,585 m3 of water, or 1,542,555,585,000 litres.George R.R. Martin has said that Westeros is around the size of South America , which is 17.84 million km2 or 17,840,000,000,000 m2. Divide 1,542,555,585,000 liters by 17,840,000,000,000 m2 and you get 86 mL of water per square meter. That’s basically four shots, which is a decent night out but wouldn't exactly turn Westeros into Waterworld.But of course the consequences of a melting wall would be more far-reaching than that. The zombies would, naturally, invade. The world would heat up without the giant refrigerator in the north, causing even more desert to spread across the eastern continent. And Winterfell would probably fall victim to floods of Wildlings, wights, and water.Whatever, it’s better than the Boltons.