Layer 1 blockchains are the foundation of crypto. Each takes a different architectural approach. Bitcoin uses proof of work with 10-minute block times. It processes roughly 7 transactions per second. The chain remains simple by limiting smart contract functionality. Ethereum pioneered smart contracts on proof of stake. It handles 15-30 transactions per second after upgrades. The network supports over 5 million active wallets. Solana combines proof of history with proof of stake. This enables 65,000 transactions per second but experienced outages in 2022. NEAR Protocol uses sharding to split data across validator groups. Each shard processes transactions independently, improving scalability. Avalanche features three interoperable chains. The X-chain handles assets while the P-chain manages validators. Subnets allow custom blockchain deployment. Each architecture makes different trade-offs between security, speed and decentralization. Blockchain #Layer1