A outlined illustration of ancient underwater temple ruins submerged in a deep ocean. Massive stone pillars covered in coral and seaweed rise from the sandy seabed, supporting what remains of ornate archways and crumbling walls. Schools of colorful tropical fish swim through the open chambers, and sea turtles glide past the decaying columns. A central altar made of dark prismarine blocks emits a faint, mysterious glow from within. Shafts of sunlight pierce through the crystal-clear water, illuminating the ruins in ethereal beams. Kelp forests sway gently in the background, framing the scene in vibrant greens.