The Whisper Gate of Black Echo Cavern

The cavern widens into a round chamber of slick black stone, its ceiling lost in darkness and its walls banded with pale mineral veins that catch torchlight like veins in bone. At the far side stands a slab-faced door carved with an open mouth, an ear, and a closed hand, while a waist-high plinth in the center hums faintly whenever anyone speaks. Every sound rolls back twice, and the floor is dusted with fine grit and old bat droppings, as if this room has punished the loudly curious for years.