Code reviews are a widely adopted practice in software engineering that is proven to increase the quality of the code. Despite its evolution in the last decade, it still presents a number of challenges, such as understanding the changeset in review. In this thesis we research the usage of Software Visualisation paradigms to aid reviewers in the change-understanding process with a tool-based approach. Based on a survey of the code change visualisation and code navigation research areas, we devise a set of candidate prototypes of a cognitive support review tool, which we iteratively refine involving developers in the process. Through an online survey, we select one of them and build CHANGEVIZ, the implementation of our novel code review environment. The effectiveness of our approach is validated with a preliminary experiment in which developers perform change-review tasks in our review environment. The results suggest that the features incorporated by our tool are valuable for reviewers.