Block Header (Metadata):

[rosebaby3892]

Distributed Ledger: Copies of the entire blockchain are maintained and continuously updated by thousands of independent computers around the world, called nodes. Every full node has an identical, complete copy of the Bitcoin transaction history from its very first block (the "genesis block" created in 2009) to the very latest.
Decentralized: Because no single entity hospitals email list controls the database, there's no central point of failure, and no single authority can alter or censor transactions. Consensus among the network's nodes is required to validate and add new blocks.
What Data is Stored on the Bitcoin Blockchain?
The Bitcoin blockchain primarily stores transaction data, along with metadata that secures the chain. Each block typically contains:



Version Number: Indicates the software/protocol version used to create the block.
Previous Block Hash: A cryptographic hash of the preceding block's header, which is the "chaining" mechanism.
Merkle Root: A single hash that summarizes all the transactions within the current block. This allows for efficient verification of all transactions in the block without having to download all of them.