Final Fantasy has four basic modes of gameplay: an overworld map, town and dungeon maps, a battle screen, and a menu screen. The overworld map is a scaled-down version of the game's fictional world, which the player uses to direct characters to various locations. The primary means of travel across the overworld is by foot, but a canoe, a ship, and an airship become available as the player progresses. With the exception of some battles in preset locations or with bosses, enemies are randomly encountered on field maps and on the overworld map when traveling by foot, canoe, or ship, and must either be fought or fled from.