Ancient Underwater City & Mermaid

great quality, best quality, anime illustration. A breathtaking, high-detail anime-style illustration of R'lyeh, the sunken city beneath the Pacific Ocean where Cthulhu is interred. The scene showcases bizarre non-Euclidean geometry, with colossal structures and shifting perspectives that blur the line between vertical and horizontal. Ancient, alien architecture built in the Paleozoic era dominates the frame, featuring massive cyclopean masonry, intricate carvings, and towering spires emerging from the deep ocean floor. Bioluminescent creatures and ethereal light particles float through the murky waters, illuminating the prehistoric cataclysm's remnants. In the center, a massive, shadowy figure of Cthulhu lies in slumber, partially obscured by the architecture, with tentacle hair and extra eyes visible. The atmosphere is mysterious, eerie, and grand, with a sophisticated color palette of deep blues, greens, and glowing accents, capturing the cosmic horror and ancient history of the Cthulhi civilization.