Mégastructure Futuriste Sous-Marine dans un Océan Turquoise

A futuristic, utopian megastructure beneath the ocean, built within a lush, natural underwater landscape; elegant, organic, bluish architecture with flowing curves; towering towers and sweeping bridges connecting elevated platforms; an advanced civilization harmonized with nature; a transparent energy field protecting from the ocean; an underwater energy shield; waterfalls cascading from cliff terraces; turquoise water reflecting below; distant mountains and marine life beyond the shield; fish swimming through the frame; small human figures walking on elevated walkways for scale; a lone explorer in the foreground holding a glowing energy staff; a cinematic, wide-angle composition; strong leading lines from the bridge to the central structure; volumetric artificial lighting; global illumination; soft, natural shadows; ultra-detailed environment concept art; AAA quality; Unreal Engine 5 lighting; high-polygon architectural detail; a clean, futuristic design; original underwater world construction; no logos; no text.