Minecraft wiki entry for Exploring_caves, associated text: While it will not help the player in navigating the cave itself, it may be wise to bring a map with them into a large cave, should the player get lost and need to dig the way out. Note that most caves occupy less area horizontally than they might seem, but interconnected caves and mineshafts can sprawl over huge distances. The player might well map some new surface as the player is exploring underground, but the cave itself will not be mapped.