Understanding the behaviour of distributed applications is a very challenging task, due to the complexity of these applications. To manage complexity, the top-down use of suitable abstraction hierarchies is frequently proposed. Given the complexity of distributed applications, manually deriving such abstraction hierarchies is not realistic. This paper discusses one tool that groups more primitive events into abstract events to derive a hierarchy of abstract events automatically. Ideally, these abstractions should reveal logical units of an application and their relations. To explore the abstraction hierarchies visualizations. A user can navigate through these abstraction hierarchies, displaying an execution at various levels of abstraction. Examples of such abstract visualizations are given and discussed. In general, the abstractions derived automatically represent meaningful parts of the application: they can be interpreted using terms of the application domain. While the abstraction tool not necessarily derives the best possible abstraction hierarchies in all cases, it does the bulk of work and provides good initial abstractions.