Modern, highly concurrent, and large-scale systems require new methods for design, testing, and monitoring. Their dynamics and scale require real-time tools that provide a holistic view of the whole system and the ability to show a more detailed view when needed. Such tools can help identify the causes of unwanted states, which is hardly possible with a static analysis or metrics-based approach. In this paper, a new tool for the analysis of distributed systems in Erlang is presented. It provides the real-time monitoring of system dynamics on different levels of abstraction. The tool has been used for analyzing a large-scale urban traffic simulation system running on a cluster of 20 computing nodes.