Many years ago, maybe the late 1980s, my students doing GCSE IT had to write a program that did something.
One had a great idea: write a program that would provide a user guide for the London Underground. The idea was that it could be on a standalone cabinet or booth at stations and people, tourists, could use it to plan journeys.
Remember, this was a time before mobile Internet, apps, GPS, 5G, anything. As far as we knew at the time, there was nothing similar available. Nowadays, apps that do this and a good deal more are very common.
My student actually visited Oxford Circus station to talk to the staff about the idea.
The program would show a central London plan of the tube. It is more complicated now, but basically the same. The central zones were chosen for simplicity, because of the sizes of screens at the time, and because that’s mostly where visitors go.
You would click on a station, click on another and the guide would tell you how to get from the first to the second, with changes if necessary.