Powerful content management system built on PHP and supported by a database engine.

Drupal is a content management system (CMS) designed for building custom websites for personal and business use. Built for high performance and scalability, Drupal provides the necessary tools to create rich, interactive community websites with forums, user blogs, and private messaging. Drupal also has support for personal publishing projects and can power podcasts, blogs, and knowledge-based systems, all within a single, unified platform.

More info:

https://www.drupal.org/