A subject closely related to moles, are tunnels, and in tunnels, what do we find?
Underground trains!
The Argentinean film "Moebius" deals with this matter.
After the inauguration of a new circular line of the Buenos Aires Underground (subte), strange things start to happen: whole trains disappear or appear at impossible locations.
In their despair, the local transport authority seeks the help of a topologist (a mathematician).
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