Is $ETH going to cool down? The most famous rollback event in Ethereum's history is the 2016 DAO hack incident. At that time, a vulnerability in the DAO smart contract code was exploited, and hackers stole about $60 million worth of ETH. The Ethereum community ultimately decided to roll back the blockchain through a hard fork, creating a new chain that excluded the hacker transactions, resulting in a network split and the creation of two chains: Ethereum (ETH) and Ethereum Classic (ETC).