> ## Documentation Index > Fetch the complete documentation index at: https://docs.celo.org/llms.txt > Use this file to discover all available pages before exploring further. # Our History > Celo's timeline from its 2020 launch as a Layer 1 to its migration to an Ethereum Layer 2 Celo launched on Earth Day 2020 as an energy-efficient and low-cost Layer 1 blockchain. Since its inception, Celo has continually evolved to adapt to the changing landscape of blockchain technology and needs of its users in the broader crypto ecosystem. *** ## The Evolution of Celo: From Layer 1 to Layer 2 This timeline highlights the key milestones in Celo's development, from its launch as a Layer 1 blockchain to its transition to an Ethereum Layer 2 solution. ### Celo's Journey from L1 to L2 Watch this video to learn about Celo's transition from Layer 1 to Layer 2, exploring the reasons behind this strategic move and what it means for the future of the ecosystem: [YouTube video player](https://www.youtube.com/embed/SGjjFpoBMfI) ## Timeline of Celo's Journey **Celo L2 Mainnet Launch** Celo officially completes its transition to Layer 2 on Ethereum, marking a new era of enhanced security, scalability, and interoperability.\ **Baklava Upgrade** The Baklava testnet transitions to Layer 2 as a final preparation before mainnet deployment.\ **Celo L2 Mainnet Announcement** cLabs officially announces plans for the Celo Layer 2 mainnet launch, outlining final steps and timelines.\ **L2 Testnet Update & Code Audit** cLabs provides an update on testnet progress and announces an upcoming code audit to ensure security and stability before mainnet deployment.\ ยท **Alfajores Goes L2** The Alfajores testnet successfully transitions to a Layer 2, allowing developers to start testing under the new architecture.\ **Preparing for Alfajores L2** The Celo ecosystem begins preparations to upgrade the Alfajores testnet to a Layer 2 environment, marking another step towards mainnet migration.\ **Dango L2 Celo Testnet Launch** Dango, the first Celo Layer 2 testnet, is launched, allowing developers and infrastructure providers to familiarize themselves with the new environment.\ **Off-Chain Data Availability Proposal** cLabs proposes integrating an off-chain data availability layer, powered by EigenLayer and EigenDA, to enhance scalability and reduce costs.\ **Celo Joins Optimism OP Stack** cLabs proposes adopting the OP Stack for Celo's Layer 2 migration to align more closely with Ethereum, reduce production time, enhance security, and maintain its unique features with minimal migration risk.\ **Quick Update on L2 Stack Selection** An update is provided on refinements in the Layer 2 stack selection process, addressing key technical considerations.\ **L2 Stack Selection Update** cLabs announces the latest developments in selecting the technology stack for Celo's Layer 2 transition.\ **Framework for Selecting an L2 Stack** cLabs provides a framework for evaluating different Layer 2 technology stacks, guiding the decision-making process for Celo's migration.\ **CEL2 Roadmap Update** cLabs releases an update on the roadmap for Celo's transition to Layer 2, outlining expected phases and milestones.\ **Gingerbread Hard Fork** The Gingerbread hardfork is implemented to prepare for Celo L2 with a focus on improving Celo's compatibility with Ethereum by streamlining code and introducing , on-chain carbon offsetting through transaction fees, enhancing both performance and sustainability.\ **Layer 2 Transition Proposal** In a strategic move, cLabs proposes transitioning Celo from an independent Layer 1 blockchain to an Ethereum Layer 2 to leverage Ethereum's security and expand its reach within the Ethereum ecosystem.\ **Celo 2.0 Announcement** cLabs announces Celo 2.0 with improved Ethereum compatibility, better performance, and enhanced tokenomics.\ **Ethereum Proof of Stake Transition** Ethereum completes its transition from Proof of Work to Proof of Stake, significantly reducing its energy consumption and addressing some of the sustainability concerns that Celo originally set out to solve.\ **Celo Donut Hard Fork** The Donut hard fork is implemented on Celo, enhancing its EVM (Ethereum Virtual Machine) compatibility and introducing cross-chain interoperability with other blockchain networks.\ **Celo Mainnet Launch** Celo officially launches its Mainnet on Earth Day, marking its debut as a Layer 1 blockchain network. Designed with a focus on energy efficiency and low transaction costs, Celo sets out to provide a more sustainable and accessible blockchain solution.\ **Ethereum Launch** Ethereum debuts as a Proof-of-Work blockchain, introducing smart contracts but facing high fees and energy consumption. ## White Papers For a deeper understanding of Celo's evolution and the technical foundations behind it, check out our . These documents cover the innovations and decisions that have shaped Celo. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.