The very elegant Tokyo subway map. Cities are inherently complex, and transit-map publishers face a dizzying set of challenges if they wish to produce a readable but accurate representation of a transit system. The designers of this map deserve particular credit for organizing and clarifying what is necessarily a sprawling collection of subway lines and stations.
At the heart of this map is the Imperial Palace. The inherent structure of the subway system lends itself well to this concentric arrangement, since the tracks themselves circle the palace, but I would also suppose that we could read into this a set of cultural and political assumptions about the importance of this central place and its inhabitants.
This map correlates strongly to how we think of the city. Much research has suggested that human minds think of locations as landmarks, and relationships between locations as simple paths that lack traditional metrics of Euclidean distance or travel time. By translating the magnitude and centrality of the Palace-as-landmark into an appropriate visual representation, we can immediately understand our place on the map as it relates to our understanding of real-world space.
More information, including maps from Osaka and Seoul.