Non-relational databases, also known as NoSQL databases, are designed to store and manage data in ways that differ from traditional relational databases. Instead of using tables with fixed schemas, they allow for flexible data models, which can include key-value pairs, documents, graphs, or wide-column stores. This flexibility makes them suitable for handling large volumes of unstructured or semi-structured data. These databases are often used in applications that require high scalability and performance, such as big data analytics and real-time web applications. Popular examples of non-relational databases include MongoDB, Cassandra, and Redis, each offering unique features tailored to specific use cases.