The Sunken Ruins of Keravnos are the remains of an ancient civilization beneath the Gulf of Keravnos. Their discovery confirmed long-standing traditions that a substantial culture once occupied land now covered by the gulf. The surviving structures include streets, halls, religious complexes, and monumental architecture built on a scale inconsistent with an isolated shrine or small coastal settlement.
A major temple complex encountered within the ruins is dominated by imagery of watching eyes and inscriptions concerned with memory, dreams, obedience, hunger, depth, and silence. Deeper chambers contain extensive use of bone, sacrificial mechanisms, psychic wards, and passages that appear to manipulate relationships between distant places or realities. The builders clearly possessed sophisticated psionic techniques in addition to conventional magic.
One of the most important artifacts recovered from the ruins was the Memosphere, a glass-like device capable of preserving and transmitting memories. Contact with it produced visions of the city before its destruction and helped establish a connection between the civilization, Visthuun, and the artifact known as the Eye of Visthuun.
The ruins are not empty. Dangerous aquatic communities occupy parts of the surrounding chasms, and an enormous inhabited settlement was observed deeper below the explored religious complex. The relationship between those modern inhabitants and the ancient builders remains uncertain.