Paris also used to have an incredibly extensive network of pneumatic mail tubes: https://www.cix.co.uk/~mhayhurst/jdhayhurst/pneumatic/book1.html https://www.ci

Paris also used to have an incredibly extensive network of pneumatic mail tubes: https://www.cix.co.uk/~mhayhurst/jdhayhurst/pneumatic/book1.html https://www.cix.co.uk/~mhayhurst/jdhayhurst/pneumatic/book1.... as did several other cities (NYC, Philadelphia, Prague, ...) to a lesser extent: https://en.wikipedia.org/wiki/Pneumatic_tube https://en.wikipedia.org/wiki/Pneumatic_tube