R’lyeh

“In his house at R’lyeh, dead Cthulhu waits dreaming."

R’lyeh is the one-time home and current prison of Cthulhu, most powerful of the Great Old Ones. It is frequently referenced but rarely encountered in H.P. Lovecraft‘s Cthulhu Mythos.

Description
A partially submerged fortress-city located in the middle of the South Pacific, R’lyeh is covered in cyclopean stonework which is difficult for mortals to look upon. This is possibly due to the nature of R’lyeh, as it is suspected to exist not only in our dimension, but in several planes simultaneously, many of which do not conform to the laws of physics as we know them.

History
Once the palace of mighty Cthulhu in times beyond memory, R’lyeh became the creature’s prison after the war against the Elder Gods resulted in defeat for the Great Old Ones. Since that time, he has remained imprisoned there, sleeping the sleep of the dead until one day his followers might free him from his captivity.

Whilst mortals have undoubtedly visited R’lyeh over the aeons, the only recorded instance of its existence comes from one Francis Wayland Thurston, who led an expedition to the island. The expedition was a disaster, with all bar two of the crew dying after making landfall. The only survivors managed to escape by ramming Cthulhu’s partially-formed head with their vessel, but soon realised that they had awoken the evil god, and in doing so weakened the bonds holding him captive. In the aftermath, all attempts to relocate R’lyeh failed, suggesting that it had either been moved, or sunk beneath the waves in order to avoid detection.