Sinjoh Ruins

The Sinjoh Ruins are a location in Pokémon HeartGold and SoulSilver that are not part of any known region. Their major feature is the Mystri Stage, a triangular stage inside the ruined temple. The only way to access the Sinjoh Ruins is by bringing an Arceus from an event distribution or an Arceus which the game recognizes as a traded Pokémon from the Hall of Origin to the Ruins of Alph. The event is triggered by having Arceus as the player's walking Pokémon and entering the Ruins of Alph. However, due to the Azure Flute never being released in Generation IV, it is not possible to obtain an Arceus from the Hall of Origin without the use of glitches or cheating.