In Lovecraft's fiction, R'lyeh is sometimes referred to in the ritualistic phrase “Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn”, which roughly translates to “In his house at R'lyeh, dead Cthulhu waits dreaming”.
Atheists believe in the Goddess Athe, who is wise and powerful beyond measure. They are some of the most religious people in the world.