The Lost Treasure of Melnah
After creating the Cataras Springs, the Fairy Circle had intended to cease in creating more World Wonders. However, an incident took place off the coast of Arcor which resulted in the eleventh World Wonder.
Captain Melnah was a notorious pirate who had raided many ships during his decades at sea. Near the end of his plundering, his ship was almost sinking from his heavy loads of loot. On the day the captain had planned to retire, he approached Arcor to find five other ships waiting for him. They all attacked his ship, fighting for shares of his treasure. However, the ship quickly sunk from damage and weight, and when some pirates dove after the treasure, they couldn't even find any signs of the ship, let alone the treasure.
This is because the Fairy Circle had intervened, a bit perturbed about the pirates' takeover of Arcor, and Captain Melnah's antics, and they had hid everything in a ruin of an old, sunken, Arcorian city beneath the Interis Ocean on the other side of the continent/island. Over the years, the pirates and others had searched here, too, but the Fairy Circle had hidden the ship among the crumbled temple and some of the treasure in the hollows of the intact statues. Over time, the treasure and its tale became legend and thereby a World Wonder. To find the treasure, one must dig into the temple and smash open the statues.