Versioning systems such as CVS exhibit a large potential to investigate and understand the evolution of large software systems. Bug Reporting systems such as Bugzilla help to understand which parts of the system are affected by problems. In this article we present a novel visual approach to uncover the relationship between evolving software and the way it is affected by software bugs. By visually putting the two aspects close to each other, we can characterize the evolution of software artifacts. We validate our approach on 3 very large open source software systems.