Izumo Ruins

The Izumo Ruins are an underground, cavernous area underneath the town of Izumo that functions as an optional dungeon in Golden Sun: The Lost Age. The entrance is well-hidden in the ring of pillars in the upper right area of the town; you must Move the leftmost pillar right one space so it is properly aligned with the others, then cast Reveal to see and enter the hole that has now opened up in the ground.

Once inside the dungeon, you will need the Parch Psynergy won in Aqua Rock and the Sand Psynergy won in the nearby Gaia Rock in order to properly explore and fully loot the cave. The main discovery within the cave is the Ulysses Summon Tablet at the end.