If the player goes far south on the map, a large brown sign will appear underwater, which is inscribed with the phrase "Here Be Dragons!".
The sign is a clear reference to old European folklore. Unexplored areas on maps (such as the coast of the Americas, or the Atlantic Ocean) would have a drawing of a dragon or other mythological beast with the caption "Here Be Dragons!" However, the game doesn't feature a drawing, and it is unlikely that an actual Dragon actually appears within the game.