The main components of a blockchain include the block, the chain, the consensus mechanism, the cryptographic hash function, and the nodes. A block contains data such as transaction details, timestamps, and a unique identifier (hash). Blocks are linked together to form the chain. The consensus mechanism ensures network agreement, with proof-of-work (PoW) or proof-of-stake (PoS) being popular examples. Cryptographic hash functions secure data integrity, while nodes maintain the blockchain network, validating transactions and ensuring its decentralized, immutable nature.