Secret chamber

@skottie17 Yeah it's right next to the alter with the big triangle cutout. However the only way to open the door is to be on the Legend of the Sunken Kingdom voyage which you can only obtain once you have acquired all 30 journals from all 6 shrines. 5 journals per shrine.

@cptnpotbeard or have someone who has journals buy you voyage. Less fun tho

@hiradc Well yeah but where's the fun in that. The journals were easy to find and good lore. Captain Amari