If you ever come to Switzerland download the swisstopo app. It is very detailed and useful for hiking but even in the city too, showing the locations of fountains, for example, rural and urban official and unofficial hiking trails, closed trails, slopes too steep to traverse, etc etc etc.

The Swiss topographical institute is a treasure.

This is where screenshots come from, official topo data are free. I use them all the time for hiking, ski touring etc. Good thing they cover also neighboring mountains a bit (to varying detail) so ie France or Italy can be enjoyed just with a single app.

Then you go further and realize how much worse free easy to find things are. There are variations of opentopomap but they lack the finesse of this.

Also available in various other layouts ie biking (veloland), canoeing or various winter sports (sadly no outright ski touring so I aproximate summer hiking paths, the best to use are still physical maps but then you need a hefty stash of various zooms at home, pricey too).

But none is perfect - opentopo map has some obscure artifacts, see ie here what I found by a chance - some hole too deep to be real, near Aletsch glacier or famous Eiger, a mountain slope in Bernese alps [1], while official Swiss topo looks like this without any such illogical artifact [2]

[1] https://opentopomap.org/#map=15/46.55901/8.07171 [2] https://schweizmobil.ch/en/map?season=summer&bgLayer=pk&laye...