One legacy of the game’s origins is a dungeon laid out on a grid: A collection of rooms, hallways and doors drawn out on an 11- x 8-inch sheet of cyan lined paper.

Good fun to be certain.

But talk to a geologist. A feature of natural terrain are vertical shafts, carved from the rock by volcanic lava tubes or eroded away by water and gravity. And let’s not forget the activities of human beings, who dig wells for that most precious resource of water and who dig mines for things like gold, diamonds, coal and iron.

Underground, there are a lot of shafts. Yet, it’s a feature that rarely gets exploited by GMs in their dungeon design.

Here are some reasons why using a vertical design can add variety to a GM toolkit.

1. It forces PCs to cope with gravity, defying it with climbing skills or use up magical resources / technology to generate flight.

2. It redefines “level.” Experienced players who’ve grown accustomed to Level 1 kobolds, Level 2 goblins, Level 3 orcs, etc., will have to adjust their thinking. The GM should feel free to adjust the monster mix in a vertical design, using monsters that can navigate the space more easily.

3.  It’s a treasure-hunter’s delight. The good stuff is at the bottom. And if the PCs think the best treasure can be found collecting at the bottom of the shaft, they can’t be the only ones. Did someone or something get there first?

4.  The creepiest most awful things lie in the deep dark. Remind players of this over and over and watch their imaginations take flight. Then make their nightmares come true.

5. Cold. Heat. Water. Ice. Lava. Cavern formations. Troughs. Waterfalls. Slides. Dropoffs. Ledges. Crevices. Any and all of these things might be put to good use in a vertical dungeon. Have fun and listen to the PCs groan.