Most metro (or subway) systems are real-life examples of complex networks with different properties. This Demonstration shows the networks of 33 of the largest metro systems in the world with graph-theoretic and visual information. Node size and edge color are depicted following a heat map determined by the degree of nodes and the centrality of edges; the larger a node, the greater the link degree, and the closer to red, the more central an edge. You can select different graph embeddings to highlight different properties of the networks. Only connecting or terminal stations are considered. Some discrepancies with current systems might exist (for example, the Shanghai metro has substantially increased recently).

[1] S. Derrible and C. Kennedy, "The Complexity and Robustness of Metro Networks," Physica A: Statistical Mechanics and its Applications, 389(17), 2010 pp. 3678–3691. doi:10.1016/j.physa.2010.04.008.

[2] S. Derrible and C. Kennedy, "Characterizing Metro Networks: State, Form, and Structure," Transportation, March 2010, 37(2), pp. 275–297. doi:10.1007/s11116-009-9227-7.