Apache Storm is an open-source distributed real-time computation system designed for processing large streams of data. It allows developers to build applications that can process data in real-time, making it suitable for tasks like data analytics, machine learning, and monitoring. Storm operates on a cluster of machines, where it breaks down tasks into smaller units called topologies. These topologies consist of spouts that ingest data and bolts that process it. This architecture enables high scalability and fault tolerance, ensuring that applications can handle varying loads and continue functioning even if some components fail.