Paris’ other underground transportation system. This is a fantastic and detailed map of the once-extensive network of pneumatic tubes used for whisking messages, post and telegrams from one side of the city to the other. Established in 1866, the system remained in use until 1984, when it was finally supplanted by “modern” technology like fax and telex machines. At the system’s apogee, there were over 460 kilometres (285 miles) of tubes running beneath the city.

Notable on this map are a few hand-drawn additions and deletions, suggesting that this map actually represents the system a few years after its nominal date of 1967. A small inset at the bottom right shows the (presumably separate and secure) governmental pneumatic tube network.

See also this map of New York’s similar network. 

Source: Eupalinos Ugajin/Flickr