Cassandra is a highly scalable, distributed NoSQL database designed to manage large amounts of data across many commodity servers, providing high availability with no single point of failure. Developed by Facebook and later open-sourced, Cassandra is renowned for its ability to handle massive data volumes and its fault-tolerant architecture. It uses a column-family data model, which offers a more flexible schema than traditional relational databases. This makes Cassandra an excellent choice for applications that require high write and read throughput, such as IoT data management, real-time analytics, and content management systems.