Imagine a grand cathedral carved from shimmering crystals, set deep within a hidden underground cavern. The walls pulse with a soft, iridescent glow, casting vibrant reflections across the stone floor. Stalactites hang like chandeliers, while a tranquil underground river flows nearby, mirroring the cathedral’s beauty. Intricate crystal sculptures of mythical creatures adorn the altar, inviting whispers of ancient legends that echo through the hallowed halls.