The series premiered in 2001. Stopped in 2005 after 27 issues, but has been revived a few times since under different titles.
The series is set in an underground science fantasy world, that is inhabited by semi-organic machine beings with souls. The world, called the Matoran universe, falls under the rule of evil powers and it is now up to the Matoran beings to free themselves.
The overall story concept comes from the Danish toy company LEGO.
(presenting the front covers from 6 random issues)