The DAO

The DAO (Decentralized Autonomous Organization) was one of the earliest and most ambitious projects built on Ethereum, launched in April 2016 as a decentralized venture capital fund. It raised approximately $150 million in ETH through a token sale. In June 2016, a hacker exploited a vulnerability in the smart contract code and drained about one-third of the funds. The Ethereum community controversially decided to hard fork the blockchain to reverse the hack, which split the network into Ethereum (ETH) and Ethereum Classic (ETC).