So what if we stick with the idea of a cave, but have a pool around the main rock where the leaders stand? There would be a hole in the ceiling, where you could see the full moon, but what if the light only shines through the hole when the moon is full and in the centre of the sky, as it is when the gathering is taking place. Let’s say that the rest of the time, a large star can be seen through the hatch, a symbol of StarClan’s faith and protection from the half and crescent moons, which are symbols of the dark forest. The rock that the leaders sit upon is made of a solid crystal gemstone, that shines blue when the full moon is upon it, illuminating the leaders. The light from the crystal could make the plants in the pool and the gemstones that line the walls glow StarClan related colours, illuminating the whole cavern and giving it an ethereal look. Cover from google