Apache Cassandra is a highly scalable, distributed NoSQL database designed for handling large amounts of data across many servers without a single point of failure. Its decentralized architecture allows for high availability and fault tolerance, making it ideal for applications that require continuous uptime and rapid data access. Cassandra employs a peer-to-peer model, where all nodes are equal, and utilizes a unique protocol called Gossip for communication between nodes. This design enables seamless horizontal scalability, allowing organizations to add more nodes to their clusters easily. As a result, Cassandra is widely used in scenarios demanding high performance and reliability.