AKANEIA is a stage in Super Smash Bros. Melee which can only be accessed through the use of an Action Replay device. Even so, the game crashes upon activation in the Debug menu. Unlike similar non-playable levels in Melee such as DUMMY and IceTop, there are no known hacks which allow AKANEIA to be accessed properly, though pieces of the stage have reportedly been uncovered from hacking.
AKANEIA is most likely an unfinished stage from the Fire Emblem universe, as it shares its name with the continent featured in the first, third, and eleventh Fire Emblem games.
In Super Smash Bros. Brawl, you can make the custom stage AKANEIA, in the picture provided. The picture is most likely the way AKANEIA was supposed to look in Super Smash Bros. Melee.