What are your favorite visualizations of Megadungeons?
Large dungeon complexes and even "megadungeons" have become a stable of fantasy RPGs. But they are difficult to map out, since they tend to be complex, three-dimensional structures. While mapping them in 5 ft. squares may be possible, that doesn't give a good view of how all the different locations connect with each other.
So I am curious: What are your favorite visualizations for megadungeons? How did they help you as a game master (or player) to understand how their whole environment is structured?