Onu-Wahi

From Lego Bionicle

Onu-Wahi was the underground reigon of Earth on Mata Nui. It consisted of tunnels beneath the earth, with small underground caves. In one such cave, Tahu's Kanohi Mask of Vision was hid. On the the ground, it was mostly just rock, sand and stone. Onu-Koro was also located in Onu-Wahi.

Many Rahi inhabited Onu-Wahi both on the surface and beneath it, for example Kofo-Jaga, Ussal Crabs and the mysterious Vatuka beast.