I am building a 6500:1 cardboard model of the Mount Rose ski resort. The whole model has a thickness of 4.5 inches at its highest point, located on one of the sides of the model. While the rest of the model tries to stick to reality as much as possible (measurements were adapted from satellite altitude data), I'm thinking about including some kind of easter egg on one of the side of the model. For instance some kind of a Bigfoot cave, or something playful in the same taste.
This being said, I'd love for this little addition to be anchored in the local native folklore. I couldn't find any reference to underground life / beings / concepts in the legends of the Washoe people with a quick google search though.
Do you know of a native Western American tale / concept / etc that could be represented underground on the side of my cardboard model?
Any help or tips would be appreciated