Cavern of Light

The Lightstone mine was an underground cavern near Ta-Koro, where Onu-Matoran mined for lightstones. On MNOG, the Lightstone mine was flooded by a lava flow from Ta-Koro, until Takua used a Lava surfboard to cross the lava flow and turn on a pump. It has presumably been destroyed recently by the Bohrok, unleashed by the Toa Nuva.