A steampunk-inspired underwater marketplace bustling with merfolk traders and Victorian-era divers, lit by glowing bioluminescent sea creatures, with octopus-shaped stalls showcasing retro-futuristic gadgets and ancient marine relics; intricate coral formations intertwine with exposed gears and clockwork mechanisms, while mysterious deep-sea currents cast shadows that dance across antique brass surfaces, creating a mesmerizing blend of aquatic wonder and mechanical elegance.