Beneath the Temple of Trias
Beneath the Temple of Trias, tunnels and rooms are said to be scattered and hiding deep secrets.  The priests dug into a large cavern that was planned to be used for catacombs but went unfinished due to a lack of gold. 

A number of hidden chests are rumored to be scattered throughout the compound as well as the private study of Father Setair.  A cell or two were also built to house those who went against the word of the gods.  The lack of gold came about after the priests spent too much on statues, exotic braziers, and traps.  They focused on decor and protection.  And that is why it has been left unfinished. 

It has been over fifty years since the Temple was vacated.  I wonder if the ruins beneath are still intact...