# What is Blockchain? A blockchain is basically a very secure database that keeps record of all the transactions recorded inside of it, forever. A public blockchain is a blockchain that is visible for everyone and works thanks to a network of nodes instead of a centralized server.**Good to know:** an employee directory can be a great way to help new folks get familiar with everyone they're going to be working with. {% hint style="info" %} Is blockchain and descentralization the same thing? Not exactly. In order to keep data in a descentralized way we need a single and immutable source of truth visible for everyone. Blockchain technologies allow us to do build descentralized networks. {% endhint %} ### Blockchain Expert Explains One Concept in 5 Levels of Difficulty by [@bwarburg](https://twitter.com/bwarburg) {% embed url="" %} {% hint style="info" %} Don't trust, verify. Public blockchain are visible for everyone to see and verify all the transactions. {% endhint %} ### How does a blockchain work? by [@savjee](https://twitter.com/savjee) {% embed url="" %} ### What are smart contracts? by [@savjee](https://twitter.com/savjee) {% embed url="" %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://indiedao.gitbook.io/indiedao/education/web3-101/understanding-the-web-3.0/what-is-blockchain.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.