A bioluminescent metropolis sprawls across the ocean floor. Schools of neon fish weave between glowing crystal spires. Manta-ray-shaped vehicles glide silently through transparent transport tubes. Giant kelp forests sway at the city's edges. Above, the surface light filters down in dancing patterns. Tiny humanoid figures in sleek diving suits move along coral walkways between domed buildings. Camera: Slow tracking shot through a coral canyon, revealing the city beyond. Lighting: Ethereal underwater with bioluminescent accents and surface caustics. Style: Photorealistic 8K, Avatar-meets-Blade Runner aesthetic. Duration: 15 seconds.