A city under the mountain: how many caverns to feed it
A fantasy city carved in the rock and fed from below on deep mushrooms, which grow on about a tenth of the cavern floor: its halls, its fields underground and how far its porters carry, size by size.
| People | Carved halls | Cavern fields | Carrying | Farmers below |
|---|---|---|---|---|
| 3,000 | 8 ha | 570 km² | 0.5 days (comfortable) | 24,000 |
| 10,000 | 25 ha | 1,900 km² | 1 day (comfortable) | 79,000 |
| 40,000 | 100 ha | 7,700 km² | 2 days (strained) | 320,000 |
| 150,000 | 380 ha | 29,000 km² | 3.5 days (not by land alone) | 1,200,000 |
Hear it
- The town: Underground City (album RPG Ambiences Vol. 9)
- The market: Medieval Village Marketplace (on Patreon, Guardian tier)
- The quays: Underground City Harbor (on Patreon, Guardian tier)
- The fire trades: Dwarven City Forge District (album RPG Ambiences Vol. 8)
- In every street: Underground Water Mill (on Patreon, Guardian tier)
- The countryside: Underground Farmland (on Patreon, Guardian tier)
Orders of magnitude for play: sourced figures and Hearth estimates together. Every source, and every figure still waiting for one, is listed in the builder under Sources.
Open the city builder — MGS Toolbox