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D&D’s Underdark: What if I told you I had a map?

Dante called it the Inferno. Christians call it Hell. Norse mythology dropped an ‘l’ to make it Hel. Buddhists call it Naraka.

Us D&D nerds might call it the Underdark. And as if they rolled a natural 20 on their perception check, scientists have found the Underdark deep beneath the Earth. They even made a map of it.

Some might be skeptical of these findings. “Subterranean caves filled with Derro and Svirfneblin certainly cannot exist,” they’ll say, and point to a YouTube video shared on Facebook to rest their case. But this is just good old fashioned geological science.

Diagram courtesy of Universe Today.

The very basics: Earth is made of tectonic plates. These immense sections of the Earth’s crust spread apart and crush together, causing things like volcanoes, earthquakes, and continental drift.

Most of us remember that part from middle school science classes, but there is deeper stuff going on as well. Subduction is a geological process where one plate moves under another and sinks into the Earth’s mantle.

A “slab” is the portion of the plate that is descending into the mantle and scientists have been working on what they are calling the Atlas of the Underworld, a map of these slabs. But *wink, wink* us nerds know that what they have really created is a map of the Underdark.

Using advanced lidar techniques and seismic tomography, scientists have used the speed of sound waves through the Earth to construct images. They are x-raying the Earth, in other words.

From this they have learned a lot about the history of the Forgotten Realms Earth. For example, the Bitterroot slab sits 120 miles below North America. Subducted about 50 million years ago, the Bitterroot slab causes the area of volcanic activity around Yellowstone National Park.

Map of the Underdark courtesy of WotC or…scientists. You decide!

I encourage you to check out the Atlas of the Underworld here. Just know that you are seeing a map of the Underdark when you look at it. Additionally, Atlas Obscura has “11 Hidden Spots to Enter the Underworld” and bill it as a world tour of the gateways of Hell. That alone is a fun read and will inspire your D&D campaign for years!

Us nerds of been fascinated by the Underdark for decades. First introduced by Gary Gygax himself, the Underdark has featured famous D&D denizens like the drow Drizzt Do’Urden, star of about 4 million R.A. Salvatore’s novels, many of which feature quotes form Nerds on Earth on the dust jackets, so we’re big fans.

The Underdark’s vast subterranean network of interconnected caverns and tunnels also serves as the home of Aboleths, Hook Horrors, Myconids, Kuo-toa, and my personal favorite, the Derro, a creature I’ve written about before.

While the Beholder is perhaps the most famous Underdark denizen, Matt Mercer’s Critical Role web series began in the Underdark, introducing new D&D fans to Duergar and Mind Flayers. The Underdark is also featured in Out of the Abyss, a major D&D storyline.

The Underdark may be a dangerous and creepy place, but thanks to scientists, we now have a handy map. Just click here to see if the Mind Flayers are living right beneath you.

Lessons learned? Science is fun, y’all. Especially when it’s mashed-up with a little imagination.