Archaeologists unearth ancient bread that survived underground for 5k years
foxnews.com
foxnews.com
The interesting part of the story is they've baked a replica (May 2025).. not discovered it (Sept 2024)
It never goes stale, as it's already concrete-like when it's fresh.
It's also the source of my favorite pun in Pratchett's vast wordplay production: the scone of stone, where dwarves royalty is coronated.