Drupal
A CMS project using Symfony packages
Drupal is an open source content management platform powering millions of websites and applications. It's built, used, and supported by an active and diverse community of people around the world. Drupal is open source software maintained and developed by a community of 1,000,000+ users and developers. It's distributed under the terms of the GNU General Public License (or "GPL"), which means anyone is free to download it and share it with others.
Official website: drupal.org