Grotto of Sacred Thoughts

The Grotto of Sacred Thoughts rested at the heart of the Undervaults of Ilsensine in the mind flayer city of Oryndoll.

Description
The temple was in a vast natural cavern, with a gigantic idol at the center that was 60 feet in diameter. The idol was made with petrified brains and was carved to form the shape of a giant elder brain. There was thirty-six tentacles that came out of the statue–all of which dug into the floor and then came out of the floor again to form column along the edge of the cavern. At the top of the effigy rested the Encephalithid which lived alongside Oryndoll's tadpoles inside the Great Pool.

The Great Pool was the spiritual, social and governmental heart of the city. The venerators in Oryndoll also organized themselves out of this temple and were responsible for maintaining the Shrines of the Great Brain.