Gateway of Echoes in the Underground City

An epic oil painting of a massive gateway carved from basalt and ancient stone, standing at the entrance to an underground city. The arch rises high with ornate wrought-iron gates and reliefs that glow faintly with rune-light. Beyond the gateway lies a vast subterranean metropolis: vaulted ceilings, stone arches, iron bridges, lantern-lit streets, and distant towers. Warm amber lamplight mingles with cool blue-green bioluminescence, creating dramatic chiaroscuro and thick impasto textures. The slick stone floor reflects the glow and the gateway itself. Stalactites hang from above, and moss and subterranean vines cling to walls. The air feels heavy with mystery and awe, hinting at a civilization preserved beneath the earth. The palette favors ochre, burnt sienna, umber, deep blues, and emerald reflections. The gateway is slightly ajar, offering a glimpse of the city beyond, with faint silhouettes of towers and glowing avenues, all shrouded in mist. The perspective is from a low angle to emphasize grandeur.