A futuristic underwater human city bathed in deep teal and turquoise light. Towering structures rise like cathedral spires, blending advance...

A futuristic underwater human city bathed in deep teal and turquoise light. Towering structures rise like cathedral spires, blending advanced human engineering with organic, coral-like designs. The architecture is laced with glowing bioluminescent energy veins in pale green-blue, pulsing like living circuits. Human silhouettes move through transparent tunnels, domed walkways, and observation decks, living and working beneath the ocean. Ethereal lights drift through the water like plankton, and mechanical sea creatures patrol silently. A single human figure in a dark exploration suit stands on a rocky outcrop, looking over the vast submerged city. The scene feels alive yet isolated, capturing the wonder and challenge of human survival deep beneath the sea.