When I first read about the Chappe telegraph, I assumed that it must have been a short lived, quixotic experiment in long distance communication.
In fact, it was a network of towers which spanned France, provided the fastest form of communication known at the time, and which was adopted in several other countries.
However, it was rapidly rendered obsolete by the invention and adoption of the electric telegraph, which was faster, more reliable and much more secure. In the cartoon, Martin only knows of one remaining tower. There are actually several left in existence (you can find them on Google), but they don’t form anything like a network.
The example of the Chappe telegraph makes me wonder what other ubiquitous aspects of national infrastructure will become obsolete in the future: perhaps petrol stations will be next.
For a good, brief exploration of the Chappe telegraph and its replacement by the electric telegraph, try James Gleick’s book, The Information.