The Rai stones are a cool example of decentralized trust with oral history being the "blockchain".
...snip...
Indeed and of course realizing that the coin base (the stones) never actually move, only the ownership is transferred.
...
Whilst we are on the subject of history, stone circles and blockchains ...
Herewith, the lost city of Atlantis !?! ...
- https://en.wikipedia.org/wiki/Richat_Structure
... and the 'richest' man who ever lived ...
- https://en.wikipedia.org/wiki/Musa_I_of_Mali