Ethereum Classic (ETC) is a blockchain that resulted from a hard fork of Ethereum in 2016 following the DAO hack. It maintains the original Ethereum chain's history and upholds the principle that blockchain transactions should be immutable.
Example
“After the 2016 DAO hack, the Ethereum community split — those who supported rolling back the theft continued on the new Ethereum chain, while those who believed in immutability stayed on what became Ethereum Classic (ETC).”