Swiss humor is a rare find, but evidence of it can be discovered in the hidden Easter eggs found in the maps created by the Swiss Federal Office of National Topography, Swisstopo. Over the years, mischievous cartographers have managed to sneak in drawings of an airplane, a fish, a marmot, a mountaineer, a face, a spider, and even a naked lady onto the maps. Some of these additions have gone unnoticed for years, only to be removed upon discovery. Despite the seriousness of their work, the cartographers found a way to inject humor into their topographic maps, adding a sense of mystery to Switzerland’s geography.
https://www.atlasobscura.com/articles/swiss-map-secrets