Software evolution is aimed at analyzing and understanding the present state of a software system and at predicting its future development. This knowledge supports reverse engineering activities since it allows the analyst to infer causes of problems in the system and to detect components which need to be restructured. However, effectively using evolutionary information is challenging because it typically comes in large amounts, especially when several years of evolution are considered. Techniques are needed to break down the data quantity and complexity. BugCrawler is a language independent tool which supports software evolution and reverse engineering1. It is based on a combination of software metrics and interactive visualizations. BugCrawler integrates structural information computed from the source code with evolutionary information retrieved from CVS log files and Bugzilla problem reports. It has been validated on several large projects.