Analyzing heap dumps containing complex dynamic data structures is essential when debugging modern software systems. However, existing tools for visualizing memory graphs can neither deal with corrupt structures such as binary trees exhibiting cycles, nor do they offer adequate abstractions when being confronted with large heaps. This paper presents MGE (Memory Graph Explorer), a memory analyzer and visualizer that combines a novel memory graph abstraction with an interactive visualization. MGE borrows ideas from separation logic and shape analysis to reveal relationships between memory nodes, names recognized structures such as doubly-linked lists and binary trees, and summarizes complex structures. This summarization works for corrupt data structures, too, and is particularly powerful for large, nested structures due to its support for interactive (un)folding. MGE’s utility for aiding program comprehension is illustrated on the basis of real-world and textbook examples and contrasted with existing debuggers.