My roommate recently showed me a video of a group of biologists who poured concrete into an anthill in order to excavate it and determine the size of an ant colony:

The results were incredible, and the excavated concrete revealed an extremely large and labyrinth-like system of paths and nodes. This can be appreciated as impressively large when you think of the relative size of the people, and especially impressive and large when you think of the relative size of an ant.

The incredibly extensive result of excavating an anthill. Even the people look small beside it.

The video led me to thinking about Montreal’s extensive underground system. If a group of biologists were to pour concrete down that, they too would discover an incredibly immense system of paths and nodes. This is even more extensive when you consider the underground city’s linkages to the metro, and those underground metro station’s linkages with smaller, micro-underground cities.  If a group of biologists were to pour concrete down Montreal’s underground city, the excavation would reveal quite the impressive system of paths and nodes as well.

Two visualizations of Montreal’s underground, offer different conceptualizations of  the geographic immensity of the system. Imagine the system’s extent when linked to the metro, and the various smaller underground cities along the metro.

Toronto’s P.A.T.H. system is similarly extensive, and itself linked to the subway, those stations themselves linking to micro-underground city systems.