Dark Meridian

The Dark Meridian (referred to by Tetsuya Nomura as the Dark Coastline) is a mysterious place in Kingdom Hearts. It is first seen in "Another Side, Another Story" (Deep Dive) video. In the first cutscene of Kingdom Hearts II, Roxas on a dark, moonlit beach, where Xemnas appears. He talks to Roxas, telling him how much he looks like Sora.

It reappears in the end of Kingdom Hearts II. After defeating Xemnas, Riku and Sora end up on the Dark Meridian. Suddenly, after Sora reads a letter from Kairi, a door appears leading them to Destiny Islands.

According to Another Report, Nomura states that the Dark Meridian is "the tip of a world", i.e. the boundary between Darkness and In Between. Sora and Riku were on the coast of the side of In Between, and were looking over the sea in the Realm of Darkness. Having said thus, the Door to Light which appeared in the ending scene is reminiscent of a quote which recurs in the Kingdom Hearts series, albeit in different words: "Deep in the Darkness, there is Light".

Trivia

 * The rocks of this place are very similar to the rocks of the End of the World, which befits this place as Riku calls it the "end of the road".
 * With the use of cheat codes, you can access this area.