This video by Talia Nassi, a senior developer advocate at AWS Serverless, explains how to build an event-driven application using Amazon EventBridge. Nassi covers the basics of event-driven architecture, where services interact through events, and demonstrates how to set up an EventBridge rule to route events from Amazon S3 to AWS Lambda. The tutorial includes a practical example of uploading images to S3, which triggers a Lambda function to resize the images. Nassi also shows how to add additional event rules without affecting existing event sources or targets, highlighting the flexibility and scalability of event-driven systems.