There's a phrase in Latin that goes errare humanum est which roughly translates as everyone makes mistakes. This is true of so many things and maps are no exception. However much we try to make today's maps as authentic, up to date and accurate as we can, the occasional mistake slips in; it's more a case of when rather than if.

But if you find a mistake in a map, is it really a mistake or it is a deliberate error, placed there as a copyright trap to provide evidence of the origin of a copied map? This is a vague area at best. Some map makers are up front about this.