Onu-Wahi

From Lego Bionicle

Onu-Wahi was the underground reigon of Earth on Mata Nui. It consisted of tunnels beneath the earth. 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.