The Great Column is a title applied to a room in the Mermaid's Tunnel (Great Aqua Cave) in the first Endless Ocean that earns its name from the three massive columns of white limestone that extend from the floor to the ceiling. This room is located at co-ordinates H/I-3, and many schools of small fish make their home here, including Oriental Butterflyfish, John Dory, Longnose Butterflyfish, and Red Sea Bream. The room before this one is unnamed, but something notable about it is that the two entrances/exits have a great difference in height, and it is home to a small shoal of John Dory.
Within the Great Column room, a piece of the Patterned Pottery treasure can be found on the floor in front of the center column under a zoom-mode glow.