How an ancient stone money system works like cryptocurrency
Archaeologists see similarities between giant coins carved from stone and cryptocurrencies
BEEN THERE DONE THAT Yap islanders in Micronesia sailed to nearby islands for limestone to carve into huge disks used as money called rai.
S. Fitzpatrick
Digital currencies, such as Bitcoin, and the blockchain technologies used to record digital transactions on a public ledger may not be so revolutionary.