_This section assumes "blockchain" already means something to you. If you're new, the central problem solved by blockchain is the ability for distributed, disparate entities to all agree on a rivalrous state of affairs. For a thorough introduction to blockchain, start [here](https://lopp.net/bitcoin.html)_
LBRY uses a public, proof-of-work blockchain that is very similar to Bitcoin. The blockchain is the foundation of the protocol stack.
The most salient feature of the LBRY blockchain is the association of a normalized string of characters (a "name") with a structured set of metadata. This coupling is called a [[claim]]. The content referenced by a claim can be accessed as a LBRY URL, e.g. [lbry://hellolbry](/playground?url=hellolbry).
The LBRY blockchain stores names and metadata in a parallel [[Merkle tree]], separate from the tree used to store transaction data. This allows LBRY URLs to be trustfully resolved even without a full copy of the blockchain.
The metadata contains information about the content, such as the title, creator, price (if any), and a unique signature allowing the actual content to be fetched from the data network, the next level in the LBRY stack.
