There's a 14th-century Irish castle with a "sunless" room - Apparently.
In the 14th-century Irish castle of Bunratty, County Clare, is a small room with walls made of a special type of stone that absorbs sunlight, rendering it completely dark. The room, known as the "sunless room", was built by the castle's owners, the MacNamara clan, as a place of solitude and contemplation. While the exact purpose of the room remains unknown, its unique design has fascinated visitors and historians alike for centuries. The castle's architecture and the room's unique feature have been extensively documented and studied by historians.