47°9′S, 126°43′W is the location H.P. Lovecraft gives for R'lyeh in "The Call of Cthulhu". Oddly, this doesn't match the location later given by August Derleth (49°51′S, 128°34′W). And both are within a few hundred miles of "Point Nemo" (48°52.6′S, 123°23.6′W), the point on the Earth's surface that is farthest from dry land.
"Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn." (In his house at R'lyeh dead Cthulhu waits dreaming.)
I hadn't known that Lovecraft had ever named a location of the place until I read "The Call of Cthulhu" on Monday. Lovecraft regarded the story as sub-standard, and with good reason...