Tiro Canyon

Tiro Canyon was a canyon in Po-Wahi on Mata Nui.

Origin
Tiro Canyon was formed along with the rest of the island when the Great Spirit was rendered comatose by the machinations of Teridax and collapsed face-up into the seas of Aqua Magna; due to the trauma sustained by the impact, Mata Nui's camouflage abilities malfunctioned, and the Island that would come to be named after him was formed over his submerged face.

Bohrok War
During the struggle with the Bohrok swarms, Gali, Pohatu, Onua and Kopaka devised a plan to trap a swarm of Tahnok in Tiro Canyon - Onua dug a tunnel from the sea to one of Tiro's cliff walls, and Kopaka plugged the entrance with his ice power. After Kopaka and Onua left (to look for Tahu and Lewa, respectively), Gali and Pohatu waited for the Tahnok to enter the canyon; when they did, Pohatu shattered Kopaka's makeshift ice dam with a well-placed boulder, causing water from the sea to flood the canyon and trap the Tahnok. Gali then swiftly swam into the water to remove the Krana from as many of the weakened Fire Bohrok as possible; this plan was complicated by the fact that the Tahnok were already heating the water in an attempt to boil the Toa of Water, but she ultimately managed to capture four Krana and escape from the cauldron. She and Pohatu were then forced to leave Tiro Canyon, as the Tahnok had already begun to climb out of the trap by melting handholds into the canyon's sides.

Destruction
Tiro Canyon was later destroyed by the Bohrok along with the rest of Mata Nui's terrain when the Toa Nuva reawakened the Bahrag.